MAKING SENSE of MEDICINE and Obesity

Study proves it's not unhealthy to be overweight? Nah.

noreply@blogger.com (David H. Freedman) — Sat, 22 Oct 2011 19:50:00 +0000

Researchers at the University of Manitoba have released a study on the relationship between body mass and health problems. Here's a typical mass-media report on the findings, headlined, "Overweight people don’t have bigger health problems, study finds."

It's an epidemiological study, which means researchers looked back at a bunch of historical data about people and then tried to draw associations between those people with certain characteristics or behaviors, and how they fared over time. Epidemiological studies are much cheaper and easier and usually quicker to do than almost any other type of study, and they seem impressive because they often involve large numbers of people. But they also are some of the least reliable studies, being typically plagued with just about every problem that a study can have, including confounders (what happens to people in the study may have little or nothing to do with the causes that are being looked at), confusion of cause and effect (what happens to people in the study may actually be causing the factors that are being studied, rather than being caused by them), unrepresentative samples (the people being studied may not be typical of the population we care about), trying to draw conclusions from small differences, and more. Most studies about the relationship between health and weight we hear about are epidemiological studies, and we've had ample evidence over time that these are some of the least reliable among generally unreliable epidemiological studies.

But there may be something else to worry about with the conclusions of this Manitoba study, something that makes me wonder if the findings are actually right--but not for the reasons implied in reports of the study.

Last year I met with Oberlin College biologist Keith Tarvin, who studies foraging behavior in animals. Tarvin explained to me that throughout most of the animal kingdom, animals will generally put on excess weight when provided with plenty of calorie-rich food and not given any reason to be physically active, such as having to forage or hunt for food, or having to avoid predators. (Animals that need to keep weight down in order to survive are sometimes an exception--birds, for example, can't fly if they get too heavy.) Situations where animals lose weight, on the other hand, are usually associated with some pathological state or threat--as for example when fish keep weight off in order stay small to be less visible to and appealing to predators, or to slow their maturation in order to preserve fertility and lower energy needs during times of drought, extreme temperatures, food shortages or other environmental pressures.

In other words--and at this point I'm merely expressing a conjecture that came up in my chat with Tarvin---it may be that, weight-related health factors aside, having a stronger appetite is associated with being well-suited to the environment. Or to put it differently, keeping weight off when there is plenty of rich food around and no pressing reason to be physically active is, in a sense, a pathological state. Apply this theory to human society today--and at this point I'm degenerating into my own conjecture--and we might well predict that being overweight is associated with being, in some ways at least, healthier than those who keep weight off.

Does this mean we should stop worrying about being overweight? Absolutely not. To conclude as much would be confusing cause and effect. If this conjecture is right, it means that being overweight is in some ways an effect of being healthy; it doesn't mean that being overweight confers any health benefits. And in fact, the possible rightness of this conjecture should have no bearing whatsoever on the well-established fact that carrying excess fat is generally unhealthy, and that people improve their health and lower their health risks when they lose excess fat.

Even if it's true that people who are overweight are in many cases healthier in some ways than many people who are not overweight, these lucky overweight would still on average even further improve their health by losing the excess weight, and those who are not overweight would become less healthy by putting on excess weight. That doesn't mean that weight loss is a pathological state, even though it's usually associated with one in the animal kingdom. We should understand that the loss of excess weight is a good thing, even if, in a way, it is an unnatural thing in our society of plentiful, overly stimulating, calorie-dense food and sedentary lifestyles. That's why our goal should be, in effect, to change what's natural in our society--so that people are pushed by everything they see around them to avoiding excess weight, rather than being pushed to consume rich food and avoid physical activity as they are today.

To have even a decent chance of proving that losing excess weight will make you healthier--or to solidly prove just about any theory about the relationship between excess weight and health--we'd need a randomized controlled trial in which people are randomly assigned to either become fatter than they are, or lose weight, or maintain their weight. That trial is never going to happen, for what I hope are obvious reasons. And this brings us back to the problems with epidemiological studies like the one done in Manitoba. They rarely answer the questions we really want to ask. Instead, they give us answers that only raise more questions. There's nothing wrong with that--it's how science operates. We should be grateful scientists are conducting these studies, and appreciate the fact that they add to our knowledge base. But we should also be aware of the extreme limitations and qualifications that attach to the findings.

In the case of the Manitoba study, I think it's fair to say the study at best tells us little about the healthfulness of avoiding being overweight, and at worst is, at least in how it's being reported, extremely and even dangerously misleading. One of the biggest problems with the obesity crisis is the lack of awareness and motivation on the part of a sizable percentage of overweight people. When a study like this gets press claiming that being overweight seems to be as healthy as not being overweight, we take a big step backwards, and cause real damage that could in principle be measured in the loss of many years of life in the population, not to mention the drop in quality of life experienced on average by the overweight. I wish scientists and journalists would start taking these issues into account in their reports to journals and the mass media.

The Impact of an Obese Presidential Candidate--Chris Christie?--on the Obesity Crisis

noreply@blogger.com (David H. Freedman) — Wed, 28 Sep 2011 17:04:00 +0000

New Jersey Governor Chris Christie continues to insist he won't seek the Republican nomination for the U.S. presidency, but many suggest he's likely to reconsider. I normally avoid commenting on any individual's weight issues, but I feel compelled to make an exception for Christie, who is obese, for two reasons. First, he's a high-profile public figure who seems to be at least flirting with those who want him to run for president, which in my opinion means he ought to expect to surrender all rights to privacy in virtually all aspects of his life, as have most governors, not to mention potential presidential candidates. Second, the president of the United States is a role model for tens of millions of people, perhaps especially including children. Anything the president does, or anything he or she is, is likely to affect the choices people make about themselves for years to come. And in this the choices relate to a serious crisis in public health.

Let me start off by saying that in no way do I have anything critical or negative to say about Christie with regard to his obesity. Obesity in general has become a major crisis for humankind, and for most individuals it is a disaster at least for health, and likely in other ways. But that doesn't mean that people who are obese have done anything wrong or inappropriate, or that there is anything deficient in their character or behavior, or that they should be given a hard time. I'd like to see most obese people motivated and encouraged to adopt healthier behaviors, and supported in their efforts to do so, both for their own sake and the sake of all us, since all of society feels the pain of the resulting high health-care costs, lowered productivity, and higher risks of obesity (given that it has been clearly proven that obese people raise the chances that the people around them will be obese, for a variety of reasons). But I'm strongly opposed to obese people being insulted or otherwise being given a hard time over obesity. Christie is no exception, public figure and role model or not. His weight doesn't in any way affect what I think about him as a person or politician.

However, I think it's fair and even necessary to speculate on the effect that having an obese president, or even candidate, could have on the public's battle with obesity. I see two obvious possibilities:

1) It makes the problem of obesity worse by allowing obese people to feel that there must not be much of a problem with obesity, since we have such an admirable public figure who is obese.

2) It would help millions to lose weight by calling more attention to the problems related to obesity and solutions available to fix it.

Which way would it go? I think it would depend on what the obese candidate or president said about obesity. If he or she talked about it openly as a struggle and discussed the benefits of and means for losing weight in a smart way--namely, through behavior change approaches--then I think this person could be the best thing that's happened to public health in a long time. If he or she refused to speak about it, or, even worse, insisted on explicitly passing obesity off as a non-problem, or made a comfortable joke of it, I think it would be a public health catastrophe.

I think there's reason to believe Christie would be the more helpful sort of candidate and president with regard to attitudes about obesity. He was one of the first and very few prominent Republicans to speak out in favor of Michelle Obama's anti-obesity campaign, defending it against widespread Republican criticism. In my opinion that makes for an excellent litmus test on this question. Ms. Obama's campaign is low-key but brilliant, hitting a real sweet spot in encouraging modest, gradual, comfortable, sustainable behavior change of the sort that could significantly improve the lifetime health of tens of millions of children. Most Republicans who have spoken out on it, meanwhile, have treated it like an evil conspiracy. It took courage and wisdom on Christie's part to go against that flow.

That Christie himself is obese wouldn't take away from any support he offers of efforts to do something sane about the public problem. Indeed, his own condition would likely add to the impact of any support he offered, and that would be true whether or not he himself is willing and able to substantially improve his health and health risks by losing some weight or speaking out on his own struggles. Were he to take those additional steps, of course, and become president, he could single-handedly become a hurricane of life-saving change in America.

One thing I can't make up my mind on is what the effect would likely be if an obese candidate or president advocated a less-sound approach to weight loss. I fear that having a president who proudly announced being on an ultra-low-fat or ultra-low-carb diet, or a fasting diet, or a drug-assisted diet, or who expressed an interest in bariatric surgery, might end up doing more harm than good. These just aren't safe and effective approaches to weight loss for most people over the long term, and embracing such an approach would lead many people to try them and end up regaining the weight, while distracting them from the behavioral approaches that can actually help over the long term. That potential damage, of course, would have to be weighed against the benefits of having a candidate or president who was at least willing to confront the problem of obesity and advocate taking action.

In any case, I truly hope voters don't make any candidate's excess weight a factor in their choices. But if we do elect a president who is obese, I hope he or she can at least on a public level become part of the solution to the obesity crisis, not the problem.

By the way, here's a video of some of the media coverage of Christie's weight vis a vis his candidacy:

Angry Responses to My Piece On Alternative Medicine

noreply@blogger.com (David H. Freedman) — Sat, 18 Jun 2011 02:34:00 +0000

First of all, my deep apologies for not posting in so long. I'm going to get back to a regular schedule, I promise.

My long article on alternative medicine came out a few days ago in The Atlantic. In a nutshell, I explain why more and more doctors are recognizing that alternative medicine does a better job in some ways with many patients than mainstream medicine does--even though the core physical treatments of alternative medicine seem to rely mostly or entirely on the placebo effect. In particular, I make the case that alternative practitioners tend to invest more time and effort in helping patients adopt healthier lifestyles and attitudes than do mainstream doctors, and these changes are likely to do more for most people's health and wellness on average than mainstream treatments.

Not surprisingly, several prominent medical-science bloggers have gone ballistic at the suggestion that alternative medicine might have something going for it. Here's a brief list of links to some of the notable, highly critical responses to the article:

Steven Salzberg's response
Steven Novella's response
David Gorski's response
Matthew Herper's response

I responded at modest length to each of these posts in the comment sections under the posts (except for Salzberg's post to the Atlantic, where my response is on a separate page. Salzberg and Novella, both highly respected scientists (and Novella is a physician as well) known to be strongly opposed to alternative medicine, were interviewed by me at length for the article, and their viewpoints were, I think it's fair to say, well-represented in the article. (Neither has suggested otherwise.) I didn't interview Gorski, but mentioned him in passing in the piece. Gorski is a physician-scientist who must be among the angriest voices on the planet with regard to alternative medicine--he is the hardest-core of this group of hard-core anti-alternative-medicine warriors--and he went after me some months ago with regard to my Atlantic profile of John Ioannidis, the highly acclaimed physician-researcher who has found so many problems with published medical research. Herper is, I believe, a lowly journalist like myself.

I'd like to make some relatively broad comments about these mostly angry responses to my article. I'll start off by pointing out that while these folks imply (they of course don't come out and say so) that they are representing mainstream medicine and indeed all of science and perhaps all of Western thought, they are not. As my article makes clear, mainstream medicine has been slowly moving toward increasing acceptance of alternative medicine. Increasingly, Gorski and other hard-core opponents of alternative medicine are themselves gradually being pushed toward the fringes of medicine. (Gorski concedes as much in his post.) Whereas I found top physician-researchers happy to say good things about alternative medicine wherever I looked, including at some the most prestigious academic medical centers in the world--I wasn't even able to fit them all into the article--I had to work a bit to line up two highly respected, articulate scientists who were intensely opposed to it so I could fairly present that point of view in the article.

Don't take my word for it--go out and ask physicians you trust what they think of alternative medicine. Yes, many still object to it, and most have some concerns and hesitations about it (as do I), but I've found that most have come to accept to some extent the fact that some of their patients, for whatever reasons, seem to get some real benefits from it, and often with problems that seemed resistant to mainstream medicine. Why would a caring physician, or any scientist, find this fact so hard to take?

Some of the attacks on my article also attempt to paint me as an alternative-medicine "apologist." But what does that even mean? Am I imagined to attend meetings of my fellow apologists where we come up with our arguments together? Apparently I'm being assigned to some terrible camp for which I'm supposed to be judged, rather than for my actual argument. Are my attackers mainstream-medicine apologists? Do any of us have to stoop to name-calling to make our points? For the record, I've never had anything to do with alternative medicine in my entire life until I took on this article, either as a patient or a journalist, and I did my best to come into it with an open mind, and with no skin in the game. If I'm an apologist for this field, I'm an incidental one.

There are two main claims that underlie all the attacks on my article. They are: 1) Because physicians could in principle provide the sort of health-improving attention to patients that alternative practitioners by most accounts are today much more likely to provide, and because it is so difficult to clearly prove that alternative practitioners do in fact do a better job in this regard, it's wrong to say that alternative medicine offers any advantage in this regard. And, 2), because alternative medicine incorporates core treatments that don't actually have the (implausible) direct physical effect claimed, but rather work by the placebo effect, alternative medicine is a fundamentally evil, anti-scientific entity (voodoo!), and therefore one must never suggest there is any aspect of alternative medicine that might be good.

I can only shrug at these notions. You'll either buy them or you won't. I don't, and most physicians don't, as far as I can tell.

Those two basic arguments underlie Gorski's particularly rabid rant, too. But if you read it, you'll quickly find yourself buried in a detailed, apparently point-by-point refutation of virtually everything I say in my article. He goes through the article paragraph by paragraph, sentence by sentence, finding in each the logical flaw, the fallacy, the error of argument. Do I compare A and B? Then I'm a fool because A and B are different! Do I contrast C and D? Then I'm a fool, because it's a false dichotomy! Do I assert a point about science? What do I know about science, I'm a journalist, and therefore a fool! Do I quote a Nobel Laureate? Then I'm a fool, because I'm arguing from authority! Do I point out a problem with mainstream medicine? Then, fool that I am, I'm setting up a straw man! Do I cite a study? Then I'm a fool, because that study was trash, or I've misinterpreted it, or it doesn't apply here! Do I say that randomized studies, the gold standard of medical science, can't really settle the question of whether alternative medicine might ultimately do a better job in some ways? Then I'm a fool, because any question can be settled with randomized trials, and in fact the studies have been done!

A brief aside about studies: There are hundreds of thousands of researchers whose careers depend on producing studies, so I'm not exaggerating when I say there is a study, and probably ten or 50 or 200 of them, for just about any reasonable question you could possibly think of, with results for each question pointing in every possible direction. And in medical science sooner or later someone manages to cobble together a version of study for each question that can be called a randomized study. When someone like Gorski sets out to prove a point, or (as is more often the case) trash someone else's, he'll point to one of these studies and cackle, QED! And when his opponent, if she is playing the same game, disses that study as junk and plunks down a different study that points in the opposite direction, Gorski will declare that study invalid in some way. And soon the two will be slapping studies down in front of each other and tearing them up like a violent game of crazy eights. I never go there. In fact, I would prefer to not quote studies at all in my articles for that reason, but editors strictly require it--I have never been able to win that argument. But I do so knowing the Gorskis out there will claim they can trump my study with their study, or howl at every point that isn't backed up by a study.

At this point, if I were anything like Gorski, I'd fire back by taking on every single point of his rant, and show why each is flawed, and why every one of my points should stand. I won't play that game, because it accomplishes nothing. (Well, I play it a little, but try to keep it short, and to assert a broader perspective.) There is no argument in the world that a Gorski can't tear apart point by point, and (you'll have to trust me on this) no tearing apart Gorski could produce that I couldn't in turn rip to shreds. You can see these sorts of mind-numbing, often semi-childish back and forths in many of Gorski's rants, since his targets do sometimes take the bait, and you can frequently see them play out in the comments underneath his posts, since he draws a crowd that loves playing this game.

The basic problem here is simply that of being unable to see the forest for the trees. Science by tradition endeavors to break down phenomena into their simplest component parts, and many scientists, and fans of science, become so enamored of this approach (which certainly has its benefits) that they are incapable of approaching anything any other way. I suspect this is why when Gorski enters an argument, he immediately atomizes. What he won't, and perhaps can't, do, is take a step back from the dueling studies and the logic errors and the flawed reasoning and the inappropriate comparisons, and instead look at the big picture objectively, and ask, What's really going on here? What might I be missing? Is there another way of looking at this? Does there seem to be some important, underlying truth that's being suggested here, a truth that may differ from the "truth" I've been clinging to, at least to some extent?

In the case of this subject, that shouldn't be hard to do. My point is incredibly simple. Our healthcare system has left physicians unable to lavish the time on patients needed to make patients feel fully cared for, or to invest time and resources in getting patients to adopt the healthy behaviors and attitudes that are so effective in lowering the risk of our most serious diseases and in relieving the pain and discomforts of many, many disorders. (I'm not even really making a controversial point here--you can read much the same in the pages of the New England Journal of Medicine of the Journal of the American Medical Association.) Alternative medicine practitioners often focus on these approaches, and many patients indisputably report that they benefit from it. Why should we care at all about medical science if it isn't dedicated to making us feel more well? But the enemies of alternative medicine are so blinded by their disdain for the "voodoo" element of alternative medicine--the fact that its core treatments depend on the placebo effect, and have no plausible mechanism--that they refuse to give an inch on any aspect of alternative medicine. Never mind that this placebo effect has been shown to accomplish wonders with regard to how patients feel, or that many and probably most of the drugs that physicians prescribe also don't do much more than placebo for most patients, along with carrying a risk of horrific side effects. And again, you can look all that up in the medical journals.

What I've tried to do in my Atlantic article, and in most of my work these days, is raise questions in areas where people already think they know the answer, but may not. I try hard to resist the temptation to claim that everyone should simply embrace a different answer, but rather merely endeavor to show that there may be a different answer, or set of answers, that work, to some extent, in some situations, for some people. I want to provoke intelligent conversation on a subject where many or most people didn't think there was anything to discuss. I want to open closed doors. But the Gorskis of the world treat intellectual doors as if it is their sworn duty to keep them tightly latched shut. They claim they're defending science. I assure you they are not. Nothing more closely represents the spirit of science than open-mindedness and a determination to put biases aside and seek out the ways in which one might be wrong. Nothing is a bigger affront to the scientific spirit than to put all one's might into trashing all arguments and evidence that threatens a preferred point of view. I estimate I've interviewed over a thousand scientists in my career, and the great majority of them were perfectly willing to confess their doubts, their hesitations, their concerns with being wrong, the questions that haunt their work and beliefs. The scientists who never give an inch when confronted with opposition to their claims and beliefs, who react with bile and disdain, who tear apart and take no prisoners, are as far as I can tell outliers, and are easily and best ignored. They can blog to their hearts' content, and win a core of like-minded fans, but in the end they won't do much harm. They're noisy preachers to the choirs.

But here's the biggest point I'd like to make about the alternative-medicine debate: Don't take my word for it, don't take the word of the Nobel Laureate or the top scientists I quote, don't take the word of the alternative-medicine practitioners I quote, and please, please don't take Gorski's word for it. Go out and see for yourself. Talk to mainstream doctors, and alternative-medicine practitioners. Talk to people about their experiences with different types of treatments. Decide for yourself whether there isn't something interesting going on with alternative medicine, something that seems to provide real help to some patients who were let down in some way by mainstream medicine. We don't all have to agree on what exactly is going on here, or whether it is entirely a good thing. But I'll bet you won't end up thinking that, as Gorski and others assert, alternative medicine is a purely evil and harmful thing that must be crushed. But fair warning: You may end being called an alternative-medicine apologist. On the other hand, you'll be in good company.

The Same Old Diet and Exercise Advice?

noreply@blogger.com (David H. Freedman) — Sat, 05 Feb 2011 17:27:00 +0000

My cover story on obesity is out in the February issue of Scientific American. You can see part of the article on the Scientific American website, but most of it is behind a pay wall. I'd love to find some way to make some of it available freely in some form online here, without undercutting Scientific American's interests. I'll see what I can work out. (Meanwhile, I see that a university has posted the full article here.)

The reader comments on the article (about 50 so far) are right there for all to see, though. They reflect a cacophony of opinions, most of them sounding rigidly held, about what has caused the obesity problem and what will make it go away. Needless to say, the Atkinites are out in force among the comments (and in blog posts about the article), lecturing everyone on how diet and exercise don't work, how everyone except them misunderstands physics and biology, how it's all carbs, carbs, carbs. They read one book by Gary Taubes (available in very long and very short versions), and they think they know more than most scientists do about metabolism and thermodynamics. Whatever the merits of the Atkins diet (and I don't think there are many for most people, nor do most scientists and physicians), the kind of disdainful, pompous, simplistic certainty mixed with gullibility and obliviousness that many Atkins fanatics endlessly spout about this highly complex subject has come to feel very tedious to me. They're welcome to their diet and their opinion, but I can only hope few would-be dieters are actually swayed by it. If you want to understand the Atkins claims, read Taubes, he's a smart guy. But before you buy the conclusions, go out and ask everyone you know how long they stuck with the Atkins diet and kept the weight off. Or just go ahead and try it (I did), but if it doesn't work for you long term, as it does not for the great majority of people (or me), please don't give up on diets. And I urge you not to give up on exercise as useless in fighting excess weight, as Atkinites suggest.

Some commenters try to dismiss the message of the article as the same old advice we've all been hearing forever about how we have to diet and exercise. That's an unfortunate point of view from several perspectives. First of all, the idea that advice should be dismissed because it's been consistently given for a long time is a troubling one. Not smoking, wearing seatbelts, drinking in moderation--this is the same old advice, too. You could argue, of course, that an article that focuses on the same old advice isn't very thrilling. What's much more entertaining is the latest and greatest breakthrough scientific finding about losing weight, or the latest diet guru's special claim on how to shed pounds with a simple change in diet. But it's the endless stream of claims for new approaches and insights that has pulled people away from what those experts who have achieved good results with the overweight have long known: you've got to focus on diet and exercise habits, and try to find ways to get people to take them up and stick to them forever. Part of the point of the article was to survey the scene and show how the same old basic advice, and not the endless stream of latest and greatest, is still what works, and what this means for the obesity crisis. What's more, the article points out prominently and at some length that there are indeed significant recent and ongoing improvements in our ability to help people stick to reasonable diets and exercise.

Yes, everyone has tried, and most have failed with, diet and exercise. But in spite of what many people believe (and some of the commenters imply) all diet and exercise approaches are not alike--far from it. A smart behavioral approach based on gradual, modest, livable changes that are strongly prompted and reinforced by others and by the environment is much, much more likely to succeed than the standard slash-calories-and-burn-up-the-treadmill plans most people subject themselves to, with predictable results. Very few people have embarked on a good behavioral program designed to bring on modest life-long lifestyle changes, rather than self-torturing in order to vaporize ten pounds in two weeks just so you can put them back on in the two weeks after.

Some people complain that I have some encouraging things to say about Weight Watchers. But the point I make in the article is that Weight Watchers is as close as most people ever get to a behavioral program, and that while it's better than most other mass-market programs and is based on sound principles, it doesn't come close in practice to being a full, state-of-the-art behavioral program that always stays true to those principles And of course the great majority of overweight people and dieters haven't even tried Weight Watchers, never mind a genuine, full behavioral program.

Well, I hardly expected the article to instantly strip everyone of their misguided obsessions with breakthrough findings and fad diets, and their distorted views of what behaviorism is about. My goal, as usual, was to try to promote discussion, and hopefully a slightly more informed, reasoned and open-minded one than one normally encounters, at least with regard to obesity and weight loss.

Of Baseball Pitches and Fad Diets: When science gets it wrong

noreply@blogger.com (David H. Freedman) — Sun, 02 Jan 2011 16:28:00 +0000

An article by John Kay in The Financial Times (and thank you, TheBrowser.com, for highlighting it) recalls economics icon Milton Friedman's and a colleague's observation that we can often get very good at something (Friedman used billiards as an example) without knowing much about the complex principles behind it. I myself always appreciated the fact that physicists used to argue that a true curveball in baseball was an impossibility and that catching a fly ball required solving trigonometric equations, while baseball players (and in the latter case even dogs) effortlessly accomplish these feats without much regard for their impossibility or mathematical demands. And it will be a long time before our best scientists and engineers can design a fighter plane whose multi-computerized flight systems can begin to approach what a fly can do evasive-flight-wise with a teeny speck of a brain--a mere 100,000 neurons, or one-millionth as many as an aeronautical engineer. The prodigious pattern-recognition capabilities and other elegant programming of our brains endow us (and other creatures) with the ability to intuit or otherwise toss off solutions that elude formal analysis.

This notion that analytically daunting phenomena are often simply accomplished by other means brings to my mind some of the interchanges I've had in recent months with metabolic experts in both the ultra-low-carb and ultra-low-fat weight-loss camps. They've got the science theory, they've got the rodent studies, they've got the diet studies, and voilà: the only way to lose weight is cut out carbs or cut out fat, depending on which camp you're listening to. The two camps come to nearly opposite conclusions, and both are absolutely unwavering and uncompromising in their belief that the science completely and clearly proves they're right. And of course there are many other scientifically sure-of-themselves diet-gimmick camps.

Back in college my math and physics professors occasionally inflicted on me and my classmates a certain type of killer problem--well, they were killers to me, anyway--in which we were presented with a step-by-step proof that started with perfectly valid assumptions, and ended up with an indisputably mistaken conclusion. We had to figure out where the proof had gone wrong. I usually had a great deal of trouble doing so--the errors were very subtle, and sometimes were semi-errors spread out among several steps. These problems left me with a deep and permanent appreciation of how right something could look in every aspect of every step, and yet end up flat-out wrong.

Though scientists and other highly trained experts should know better--for one thing, I would think most of them got that same kind of what's-wrong-with-this-picture? problem in college--these folks often seem oblivious to the way that very right-sounding arguments can leave them impaled on silly conclusions. Of course, one of the main points of science is supposed to be to test theories to avoid this problem, but, as I've discussed endlessly elsewhere to the point where I'm tired of hearing myself repeat it (though fortunately others have been smartly chiming in on this subject lately) these tests tend to be terrible, and typically end up merely reflecting researchers' biases rather than getting at any real truths. In the end, the scientists who do the best work tend to be not the ones who avoid bias--that's just about impossible--but rather the ones who for whatever reasons end up with the right biases. When an expert's instincts run off the rails, you get, well, for example, claims that fat or that carbs are entirely responsible for obesity. And these experts become so convinced that the science and data back them up that their beliefs become unreasonably unshakable

This willingness of intelligent, knowledgeable people to let solid-seeming scientific reasoning make them absolutely certain about what is obviously not so is remarkable. There's so much easily observable evidence in the world all around us that people are able to lose weight and be healthy while still eating carbs, or still eating fat, that it just feels silly to have to make a point of arguing it--if someone doesn't see it at this point, they've just decided not to see it. Tens of millions of people have tried the Atkins-style ultra-low-carb diet--it was initially a fad diet in the 1970s, and was reignited as a much bigger fad in 2002 after a New York Times Magazine cover story outlined the science that seems to back it up, an article written by the brilliant science journalist (and my friend) Gary Taubes. Meanwhile, tens of millions more have tried very-low-fat diets. How has that worked out for America? We all know the sad answer to that question. Out of the dozen or so people I know personally who went on the Atkins diet, not a single, solitary one kept the weight off for more than two years, and most lasted on the order of a few months. (Some years back, after getting a very convincing science lecture one-on-one from Taubes, I tried it, and lasted three weeks--I felt like crap the whole time, though I don't seem to be typical.) I know a few people who lost weight on very-low-fat diets and actually kept it off, but they didn't really stick with the diet--they added back modest amounts of fats back in, and they also happen to be very physically active people.

Needless to say, what happens to my personal acquaintances hardly constitutes convincing evidence. But if you look at the range of diet studies out there and talk to a lot of experts in the field and others about what has and hasn't worked--something I've been doing quite a bit of for the past year--it becomes utterly clear that neither of these extreme diets achieves particularly good long-term adherence levels, and without long-term adherence a diet is at best a waste of time. To be sure, some people do permanently lose weight on one or the other approach, and in the Internet era a small minority of fad-diet beneficiaries can band together on websites and blogs and sound like a movement. More power to you if you're one of these beneficiaries. But clearly for the vast majority of people cutting out carbs or cutting out fat is simply not going be a lifelong habit. It doesn't matter whether cutting carbs or cutting fat will actually help you lose weight and be healthy--and it certainly doesn't matter if the science appears to back the approach up--if you can't stick with it. What we need, of course, is eating and exercise habits that we can stick with, and ways of being helped to adopt and stick with healthy eating and exercise habits. Cutting back at least a bit on carbs and/or fat is usually part of it, but it's not typically the main part, and it's rarely the entire shooting match. Having to drastically cut back on a major food group usually makes an eating plan nearly impossible to stick with long-term for most people. (But for those of you who insist on doing so, you might want to cover your bases with the Dukan Diet, a big fad diet in France that is now making its way to the US, and which advocates cutting out both fat and carbs, leaving you eating mostly protein. Good luck! In its defense, I'll point out that it does also advocate behavior-oriented measures. On the other hand, many medical experts caution that eating very-high-protein can be dangerous over the long term.)

I've tried talking to various advocates of extreme diets about these seemingly obvious problems with their claims and it's like talking to someone about deeply held religious beliefs. (Actually, some deeply religious people I've spoken with are much more open-minded about their beliefs than are some people who cling to dubious scientific beliefs.) Taubes is one of the smartest people I know, and he has surely become one of the most knowledgeable people on the planet with regard to how the human metabolism deals with sugar, but I just have to scratch my head over his (and his hard-core supporters') response to the observation that working on behavior change seems to be a critical factor when it comes to permanent weight loss, the response essentially being, "All eating-related behavior is driven by carbs and their effect on metabolism, exercise doesn't matter, the science proves all this, and that's that." Low-fat proponents, at least the ones I've interviewed, tend for whatever reasons to be much more aware of the role of behavior change than the somewhat fanatical very-low-carb crowd, but can be as tenacious in their patently implausible claim that a single type of food is largely responsible for obesity. Both low-fat and low-carb fanatics are of course very good at pointing out the holes in the scientific reasoning and evidence of the other camp, but blind to the holes in their own claims.

One of the things I really like about experts who focus on behavior change, and especially applied behavior analysis researchers--the folks who study ways of applying what is essentially B.F. Skinner's science of behaviorism--is that most of them rarely seem to get hung up on theories. They just try to figure out through observation of people what best works in real life--either for an individual, or for the greatest percentage of people in a group--and then that's what they push, while they continue to look for something that works even better, or on a broader range of people. It's very hard to picture a behaviorist insisting that a pitcher can't possibly make a baseball curve, or that eliminating carbs is a necessary and sufficient condition for shedding weight.

Dazed and Carbfused in the LA Times

noreply@blogger.com (David H. Freedman) — Mon, 20 Dec 2010 14:20:00 +0000

To hear (for example) the Los Angeles Times tell it, there has been a reversal of opinion about what causes people to be overweight and unhealthy. Specifically, it used to be all about fat, but now experts realize it's all about carbs.

Really? I don't think that's even close to being a fair representation of the consensus of expert opinion over the years or now. It's true, eating very-low-fat was all the rage in the 90s, and there has certainly been a lot of noise made more recently by people who claim eating very-low-carb will solve our weight and health problems. But the fact of the matter is that a pretty large percentage of experts--or at least those experts who have actually been directly studying and working with significant numbers of overweight people and helping them lose weight--have fairly consistently maintained that the real problem is taking in too many calories and not burning enough of them. Yes, reducing fat was considered the prime target for many years, and reducing refined carbs is considered an especially good target right now, but for most experts the real goal is and has been all along to reduce intake of calories, and reducing both fats (especially saturated fats) and carbs (mostly refined carbs) has been and continues to be seen as an especially good way to do that. I'm 56 years old, and when I was a kid everyone knew that eating foods loaded with sugar and flour was a terrible idea if you were trying to lose weight--and it wasn't exactly breaking news then, either. It's just plain silly to claim that there has been a recent realization that excess consumption of sugar and white flour is a big contributor to obesity.

So why do some journalists seem convinced there has been a massive shift in opinion? Part of the problem, apparently, is that although obesity tremendously increases heart-disease risk, heart disease is actually one of the few serious illnesses that modern medicine has been able to get at least a bit of a handle on, and the mortality numbers for heart disease have been improving. But that good news has been somewhat offset by the fact that Type 2 diabetes is becoming a much bigger problem in society, and while that disease is also closely linked to obesity, excess consumption of refined carbs does indeed seem to be an especially risk-raising factor. That's what the LA Times article emphasizes.

But what that article and many others overlook is that while certain types of foods may play special roles in raising risks for particular diseases, obesity tends to be the overriding risk factor. Staying at a healthy weight, almost regardless of how you do it, is what's most likely to lower your risks of heart disease, diabetes and cancer (not to mention other benefits such as increased energy and mobility). If you eat very-low-carbs but end up overweight anyway you'll be at much higher risk of disease than someone who manages to get to and remain at a healthy weight while continuing to eat generous amounts of carbs. Relatively few experts dispute this fact.

What's really at issue, then, is whether being on a very-low-carb diet is more likely to help you lose weight and keep it off permanently than are other types of diets. You'll hear very-low-carb advocates (like the experts quoted in the LA Times article) citing all sorts of studies in which these diets brought on impressive weight loss, with of course the expected improvement in health markers that almost always goes along with losing weight. But please, before you ever allow yourself to make any weight-related diet or other lifestyle decisions based on any of these studies, do yourself a huge favor and do the following two things. First, note how long the study went on for, and if it's less than two years, ignore it completely. Researchers have been able to get people to lose weight on just about any sort of diet or lifestyle modification--a point colorfully illustrated recently by the professor who lost weight on a snack-cake diet. But researchers are usually not able to demonstrate that special diets enable people to keep the lost weight off for much more than a year, and often these studies (like the one most prominently cited in the LA Times article) only last a small number of weeks. Second, if you come across a long-term study that seems to suggest a particular type of diet did the trick in helping people keep the weight off, make a point of looking up other diet studies to see for yourself that advocates of other types of diets can make the same exact claims. The bottom line: studies in aggregate don't clearly support any particular type of diet over others for long-term weight loss. If you've been reading other posts in this blog, you know what I'm going to say now: The way to lose weight and keep it off is to make gradual, comfortable, modest changes in your diet and activity so that you slowly move towards eating healthier, less-calorie-dense foods and more daily physical activity as routine, lifelong habits.

Now having said all that, let me say, as I've said all along, that (preferably gradually) reducing your intake of sugars and other simple carbs (especially by subbing in other, preferably less calorie-dense foods) is a great goal in a behavior-change-oriented approach to losing weight. Simple carbs often make up a huge percentage of calories in many people's diets. Yet they are among the biggest offenders when it comes to providing that insidiously wonderful sensory experience that serves as toxic instant gratification for people who tend to overeat. What's more, simple carbs are metabolic gunpowder, in that they tend to spurt as sugar right into the bloodstream, which (to oversimplify a complex picture) causes the body to overreact by producing too much insulin and quickly removing all that sugar. In other words, simple carbs cause your blood sugar to spike and then plunge. The result of a plunge in blood sugar is that you feel hungry. So eating simple carbs not only rewards you for overeating on a sensory level, it also makes you hungrier. Or at least that's how it seems to work for many and probably most people. (And a constantly repeated carb-exacerbated blood-sugar spike and plunge can also eventually help bring on Type 2 diabetes, which is why simple carbs are linked to the disease.)

So yes, people who want to lose weight should generally make reducing simple carbs a key goal. But--and this is a big "but"--there is very little evidence that going quite a bit further and virtually eliminating your intake of carbs altogether, including complex carbs such as whole-grain foods and beans and other legumes, is a very good idea at all. And yet doing so is exactly what a very vocal group of ultra-low-carb extremists insists we all must do to become healthy. The ultra-low-carb crowd doesn't merely claim that its approach is a good way to lose weight. It doesn't even merely claim that it's the best way to lose weight. It claims that it's the only way to lose weight. That's right--according to these folks, it's not biologically possible to lose weight and keep it off unless you drastically cut down on your intake of all carbs, because carbs make your body produce fat, whereas other foods go into fueling muscle activity. They "prove" that this is true by detailing metabolic processes at great length and citing all sorts of studies, relying heavily on rodent studies and short-term weight-loss studies. And of course they highlight their own personal successes with very-low-carb diets. (By the way, when I say "all" carbs, I'm being a little imprecise. In fact, even ultra-low-carb enthusiasts recognize that fiber of the sort found for example in green vegetables, though it's technically a carb, is fine and even desirable in your diet. So understand when I say "carb" I'm leaving fiber out of it, because there's just no controversy there.)

Please don't mix up the good advice to significantly reduce simple carbs with the somewhat extremist advice to almost entirely eliminate all carbs. The former is considered good nutritional advice by just about everyone, and in fact it really more or less always has been. The latter, which is of course essentially the Atkins diet, is considered to be not a good idea by most experts--the Atkins diet is widely considered a fad diet. Why? Well, for one thing, as appealing as it may be to imagine that all you need to know about weight loss is that fat just melts off when you cut out carbs and comes flying on when you don't, the ultra-low-carb crowd has to do some pretty amusing backflips to explain how whole swaths of the planet (especially in Asia), and countless thousands of people in studies, and probably many people you know personally (maybe you yourself!), have managed to stay trim, and in many cases lose weight and keep it off, while still eating at least moderate amounts and in many cases plenty of all kinds of carbs. Needless to say, low-fat proponents present a different picture of how the metabolism deals with different types of food and cite different studies to produce an equally impressive-sounding (and possibly ultimately equally specious) case that reducing fats is the secret to losing weight. What's more, many and possibly most experts are concerned about the possible negative health effects of diets that are extremely low in all carbs, at least in part because these diets are inevitably very high in fats. (Most ultra-low-carb extremists insist eating loads of saturated fats is perfectly healthy, and that especially worries a lot of experts.)

But to me, while these objections are well worth considering, they're not the biggest problem with the claim that we all need to cut out all our carbs. The biggest problem would be that the ultra-low-carb diet, having received all kinds of publicity over the past 40 years, has by now been tried by tens of millions of people, and by all evidence only some minute fraction--perhaps a few percent--actually end up staying with it and keep on not eating carbs for many years. Is that surprising to you? Do you really think you can give up not only all sugar and white flour, but all grains, beans, fruit, rice, and potatoes for the rest of your life? Come on--this is a massive, drastic change in behavior, and it has to take place and permanently stick in a world where these delicious foods are ubiquitous and highly appreciated, and have always made for a significant part of just about everyone's diet. Short of making carbs disappear from the planet overnight, I just think it's silly to imagine some significant percentage of the population swearing them off and being able to hew to that plan for the rest of their lives. That's why when you talk to people about the Atkins diet you hear the same story again and again: Tried it, lost weight without being terribly hungry, thought it was the greatest diet ever, eventually got cravings, cheated a little, cheated even more, caved in and went back to carbs, gained all the weight back and more. Yes, there are apparently thousands of people out there who really seem to have adapted to a permanently carb-free lifestyle. I say congratulations, and more power to them. But remember, take any goofy idea and you'll find thousands of people out there who have made it work for them, and who then become determined to convince the rest of the world that it's the only way to go. Some articles in the mass media, like the LA Times article, vaguely make it sound as if the experts widely back this extreme point of view. But go and search out other articles that back this point of view, and you'll see the same handful of experts trotted out to make the same claims. They're a real minority among experts in the field.

When you read about some study that shows reducing carbs helps with weight loss and health, or about some expert stating what a good idea it is to lower carbs, don't assume they're talking about the extremist position of near-total carb elimination. Journalists may occasionally conflate the two very different positions to suggest there has been some giant sea-change in thinking about carbs, but it's not really the case. Yes, it's fair to say there is now more attention being paid to carbs than before, and reasonably so, but the basic advice has actually been fairly consistent for decades: Take it easy on simple carbs and especially sugar, and take it easy on fats and especially saturated fats, because these are both sensory-stimulating, high-calorie-density foods. These are well-established strategies that have been known for decades to help with weight loss that can be permanently maintained.

Now quit reading blogs and go out and take a brisk walk. Then come back and reward yourself with a small bowl of your favorite complex carb.

Should the Non-Obese Mind Their Own Business?

noreply@blogger.com (David H. Freedman) — Wed, 15 Dec 2010 15:07:00 +0000

Is it right to push the overweight to shed their excess fat? In spite of the many strong and simplistic opinions that continue to be loudly expressed on this question, it is actually a charged and complex one that deserves some careful and nuanced consideration.

First of all, ought we as a society or as individuals have any say in what sort of weight it's OK for others to carry? The arguments from one side: As Sarah Palin puts it, it is among our "God-given rights" to be obese; it may not even be as bad from a health perspective as everyone makes it out to be; and besides, the overweight are typically powerless to do anything about it, so why make them feel bad about it? From the other side: Obesity is, according to a wealth of evidence, a major health crisis that affects all of us, in that the burden that obesity-related disease places on the health-care system raises everyone's health-care costs; obesity is associated with lower productivity that hurts the economy; and the prevalence of obesity makes it more likely that children and others will become obese, because as social creatures we closely influence one another.

Does pushing the overweight to lose weight even accomplish anything? On one side: The overweight already want to lose weight, and many have tried desperately to do so, so giving them grief about it only makes them feel worse, and in fact it tends to be counterproductive. On the other side: Many of the obese aren't working at diet and exercise, and may not even see their or their children's excess weight as much of a problem, suggesting there's room to usefully raise consciousness; and doctors, public-health officials, early education providers, loved ones and close friends, at least, can't be expected to stay mum as people they care about or are to some extent responsible for remain on a collision course with obesity-related disease.

Is losing weight simply a matter of taking responsibility for one's behavior? On one side: Anyone can lose weight--just eat less and exercise (or do whatever magic one-size-fits-all solution you believe in, be it cutting carbs, or cutting fat, or drinking water, etc.). On the other: It's in the genes, and diet and exercise won't fix it.

My own take on these questions:

· I think it's absolutely fair for any of us to get involved in encouraging the overweight to lose weight, because of the hard and soft costs to society. It's real money, it's our money, and it affects our children.

· I think attempts to push the overweight into losing weight are frequently ineffective, harsh and stigmatizing, and that's just unfair, unreasonable and even cruel. We ought to only push in certain, careful, helpful ways, and only so far. Instead of being confrontational and critical, especially on a personal level, it's much more reasonable and helpful to make changes in society that will make sure everyone gets the right messages about health, and is prompted to eat healthier food and become more active. We can make these changes in schools, in the workplace, in foodstores, and in the media. And we can make more and better behavior-change resources available for individuals and families. At the same time, we need to stop muddying up the picture with the sort of distorted messages that encourage people to either downplay the problem of obesity or to think that fad diets, excessive exercise, surgery or pills can fix it.

· I believe most people who are significantly overweight, with some exceptions, can lose weight and become far healthier by changing diet and becoming more active--they are absolutely not doomed by genes, in spite of all the anecdotal evidence and highly flawed studies that are held by some to suggest otherwise. But that's not the same as saying the overweight need to get on the ball and fix themselves. It's clearly extremely challenging for most people, overweight or not, to simply cut way back on their calories or take up intense exercise regimens and then maintain the weight lost that way--our bodies and brains fight that sort of traumatic intervention with everything they've got. But if we can fix the environment and otherwise help the overweight into making a series of relatively small, gradual, easy-to-live-with changes that become lifelong habits, most overweight people will benefit from it, and without having to submit to futile self-torture. If our involvement takes the form of assistance and encouragement and support, then we can help make a difference instead of merely being nasty gadflies. That attitude puts the blame for obesity where it belongs: on all of our shoulders.

I know many and probably most overweight people simply want to be left alone about it. But I don't think we're obligated to respect that wish--not if it's a condition that affects all of us. Let's just make sure we're being reasonable, respectful, caring, wise, and helpful about the sorts of tactics we bring to bear.

Misunderstanding reward and punishment in obesity and fitness

noreply@blogger.com (David H. Freedman) — Tue, 23 Nov 2010 17:11:00 +0000

I frequently run into the contention that enlisting food--typically dessert or other treat foods--as a reward for someone who is trying to lose weight is a terrible idea because it will make the person like food more. The theory here, apparently, is that we learn to associate whatever is used as a reward with good feelings, and so it becomes more desirable. The same supposedly goes for punishment, in the opposite direction: We end up developing a strong distaste for what is used to punish us. One fitness expert I've been following on Twitter, and for whom I have tremendous respect, has been arguing lately that when gym teachers punish children for not following directions by making them, say, run laps, the kids end up being "programmed" to hate exercise.

Though almost everyone seems to accept this reasoning--apparently the notion just strikes people as intuitively obvious--there's really badly muddled thinking behind it. The basic problem is that this thinking confuses the causes and effects of reward and punishment. In general, you won't at all like something more because it's enlisted as a reward, or dislike it more because it's used as a punishment. Why would you? If your boss decided to reward your excellent performance with the honor of emptying the department trash, would you start to like emptying the trash? I doubt it. If your boss said that every time you fail to meet your annual objectives he was going to punish you by sending to Hawaii for a week, would you come to hate going to Hawaii? I don't think so. Having something enlisted as a punishment or reward doesn't in general have a big effect on how much you like or dislike it. It's the other way around: something serves as an effective punishment or reward because you already like or dislike it. If you like something that someone tries to use on you as a punishment, then it won't be a punishment, essentially by definition. The person may intend to punish you, but he's actually rewarding you. The same holds for trying to reward you with something you hate--you won't end up liking it, you'll just find it very unrewarding.

An effective reward or punishment changes how you feel about the behavior being rewarded or punished, not how you feel about the reward or punishment itself. If your boss sends you to Hawaii to reward your excellent performance, you might well feel much more motivated to perform your job well. But it won't cause you to like going to Hawaii, you already liked going to Hawaii, which is why your boss was clever to chose it as a reward. If she chooses to reward you with the job of emptying the trash, you won't be programmed into disliking emptying the trash, you already disliked it, which is why it was a really dumb choice of reward, and will not likely inspire you to work harder. The same goes for using food as a reward or running laps as a punishment. You like the food treat, so you'll work harder to get it as a reward--but it won't cause you to like the food more, you already liked it. If a kid likes running laps, then the coach is being foolish to make the kid run laps as a punishment--it won't be a punishment at all, and won't make the kid dislike running laps. If a kid already dislikes running laps, then the coach is indeed effectively punishing the kid by making her run laps--but it won't be programming the kid to hate running laps, the kid already didn't like running laps.

Now, there can be complicating circumstances that blur the picture a bit. For example, someone can turn something you like into a punishment by making you overdo it. For example, you might like running, but someone could punish you by making you run brutally long distances in the cold and rain, and that might indeed change your feelings about running. But you didn't like running brutally long distances in the cold and rain in the first place, so it's not really the same thing as being made to dislike something you liked. Also, having someone want to punish you might fill you with guilt, shame or even self-loathing, and those feelings might be intense enough to end up tainting your feelings about whatever it is that is nominally enlisted as punishment, even if it were something you liked--so in that sense, you can end up being made to dislike what's being used to punish you. But if you're feeling guilt, shame or self-loathing over your behavior, then that's the real punishment--it's an internal, self-inflicted one--and the imposed external "punishment" is really just something superfluous that you're being accidentally conditioned to associate with those feelings. (To get a bit technical, it's more Pavlovian reflexive conditioning than Skinnerian punishment, which is really a different animal. You'll know what I mean if you're familiar with the 1971 Stanley Kubrick film A Clockwork Orange, based on the novel by Anthony Burgess, where Beethoven's music becomes accidentally associated with the feelings of nausea and dread forced on the protagonist when he's exposed to violence.) And of course all this works the same way for reward, in the opposite direction. But this sort of accidental conditioning with superfluous reward and punishment isn't likely to happen in most food-treat and lap-running situations, or in most everyday situations. If you feel that badly about having done something you shouldn't have, you're probably just not going to do it very often, so no one will feel a need to tack on a misguided "punishment." If you feel great after you do a certain thing, you're probably going to do it on your own, without requiring a food treat.

Actually, food is a great reward in a weight-loss or fitness program. Behavioral experts who have studied fitness and/or obesity--in other words, real experts on reward and punishment, and who by the way tend to be in great shape themselves--routinely use food as a reward. One researcher told me about an obese, previously sedentary child who is now losing weight in part through daily walking. How did the parents get the child to take up walking? By allowing him to pick out a small, favorite food treat at the store--as long as the child walks there and back with the father. One of the top obesity-focused behavioral researchers in the country told me he rewards himself with a mango smoothie after a run, and that he finds himself thinking about that smoothie when he's about halfway through the run, which helps pull him along--and he helps others keep to their exercise plans with a similar use of food treats. I always reward myself for completing a workout with a small sundae-like treat, and absolutely find it helps get me through the last few sets of crunches or pull-ups or whatever.

Now I do happen to think conventional PE classes (where they haven't been lost to budget cuts) are a potential nightmare to lifetime fitness, and do indeed cause some kids to dislike participating in exercise. But that's not because exercise is routinely used as punishment in these classes. The exercise is usually meant to be fun and to make kids feel good, because the gym teacher herself probably always enjoyed and felt great about participating in sports and exercise. But the grueling training for fitness tests, the intensely competitive ball sports, the difficult gymnastics, the exhausting wrestling matches--this is all stuff that many kids don't like doing, so these kids are unintentionally being punished for participating. Even kids who do like this stuff aren't likely to keep it up much beyond high school. Instead, I think PE classes should emphasize establishing moderate, comfortable, enjoyable exercise as a daily lifetime habit, with the more intense, athletic, competitive stuff perhaps offered as an additional option for those who truly enjoy it. Taking it easy on kids in PE class wouldn't be promoting athletics as strongly, but we're not much of a nation of adult athletes anyway. Better off settling just to get us to not be sedentary as adults. If America were by and large a nation of walkers--or bikers, joggers, casual weightlifters, dancers, or any kind of physical-activity-doers--I firmly believe, as do many experts, that we wouldn't have an obesity crisis, and we'd be far, far healthier on average.

5 reasons why the discovery of the Fat Gene won't help you lose an ounce (and might cause you to gain weight!)

noreply@blogger.com (David H. Freedman) — Mon, 15 Nov 2010 02:53:00 +0000

The headline: "Discovery of 'fat gene' raises hopes for fighting obesity"

The five reasons:

1) Mice! The study was conducted on mice, and most research on mice doesn't end up translating to humans.

2) Genetically engineered mice! The study was conducted on mice whose genes had been tinkered with, and findings from these studies are often even shakier, because no one really knows what these animals are. They're usually tinkered with in a way that's supposed to make their disorder more like a human disorder, but these imitation disorders rarely turn out to be good stand-ins for the real thing. And the resulting mice aren't exactly normal mice anymore, or at least breeds of mice that anyone is familiar with. So you just don't know exactly what to conclude from studies based on these critters. Very few practical treatments have come from studying these "transgenic" mice. (Which is not to say they aren't marvelous contributors to basic science, and we should all be big supporters of basic science. But basic science, by definition, won't do anything for you--not until someone figures out how to turn it into applied science.)

3) You're stuck with your genes. Even if the Fat Gene discovery translates to humans, what are we going to do with the knowledge that you have this gene? If you do have it, then presumably you're fat, but you probably knew that already, didn't you? There's gene therapy, in which you're injected with a virus carrying a gene that the virus can insert into your cells to replace the trouble-making gene. But gene therapy ran into some ugly problems in the early days just over a decade ago, and though more recent results have been encouraging, I haven't heard anyone in a position to know claim any gene therapy is likely to be widely available, or available for non-life-threatening conditions, any time soon, it's just considered too risky. The discovery of the Fat Gene might in theory lead to better diet and exercise advice based on knowing you had the gene, but that's unlikely--everything has been tried, diet-and-exercise-wise, we know what works and what doesn't, and it tends not to differ in major ways from person to person, regardless of genes. On the other hand, if a certain gene, or an overactive copy of a gene, were identified by itself as truly the major cause of being overweight, the goal would be to develop a drug that counteracts the effect of the gene. (Or if it's the absence or non-functioning of a gene causing the trouble, a drug that would work in its place.) In other words, discovery of the Fat Gene will lead to the Fat Pill! Except that...

4) ...Gene discoveries don't end up leading to good new drugs. Not so far, anyway, in spite of a few decades of trying. The problem, as many leading molecular biologists, including some who actually work for pharmaceutical companies, have told me, is that individual genes rarely cause problems by themselves, they usually work as a part of a network of hundreds of genes that work together to cause the problem. So taking a pill that counteracts the effect of the one gene wouldn't solve the problem. Even if the gene did mostly cause the problem on its own, any drug you take to try to counteract what the gene is doing would almost certainly end up interfering with the work of other genes, and with other functions that one gene is performing. In other words: side effects. That's why most drugs don't do much good for most people, and end up doing harm to some people. That's true even of drugs that make it to the market, and even of drugs that become best-sellers, let alone the thousands of experimental drugs that get washed out along the way.

5) Big gene discoveries rarely hold up. Just wait. In a couple of months, you'll see studies that show this gene doesn't seem to be a big deal after all. If you look for the studies, that is. The discovery that a previous discovery wasn't the big deal it was made out to be rarely makes headlines. Everyone either just forgets about the original big discovery, or mistakenly thinks it's still considered a big discovery. But you'll be ahead of the game, because now you know right off the bat why it's probably wrong to think of the Fat Gene as a big discovery. Although...

6) ...Maybe it really is the Fat Gene. Hey, sooner or later scientists will actually be right about one of these things. And I will have been wrong. It could be this time! Let's hope so. But in the meantime, please don't ease up on your commitment to staying healthy by eating sensibly and getting regular, enjoyable exercise in. If you do slip back to your old, unhealthy ways because you think science is going to save your butt, then all the discovery of the Fat Gene will probably have done is make you fat.

Scary cig pix are old hat elsewhere. Fried chicken next?

noreply@blogger.com (David H. Freedman) — Thu, 11 Nov 2010 04:11:00 +0000

It's great that the FDA is trying to get gruesome, graphic, smoking-harm-related images on cigarette packaging. It's also about time, considering some other countries have been doing it for a while. I took this picture a few months ago about 60 feet outside of the US at the Canadian border crossing next to Vermont. This is a classic behavioral technique: Tweaking the environment to prompt desired behaviors, or discourage undesired behaviors. Let's get this done for cigarettes, and then move on to junk food. My whole interest in behavioral approaches to obesity was first prompted by a cancer researcher in the UK who told me he thought cans of Coca-Cola should be treated like packs of cigarettes. Enjoy!

What four new studies hint about fixing obesity

noreply@blogger.com (David H. Freedman) — Fri, 05 Nov 2010 02:50:00 +0000

Four recent obesity-related studies have come out in the past few days that are worth taking a slightly closer look at. One reported that overweight people who have successfully taken and kept off weight tend to stick to structured exercise programs. Another found that male rats made obese and diabetic via high-fat diets tended to have diabetic female offspring, while male rats given normal diets did not--and since there was no general difference between the genes in the two groups, and because the mother rats in both groups were non-obese and non-diabetic and so couldn't have passed along anything different in utero, the explanation lies somewhere in environmental differences relating to the dad rats' different diets. (Yes, rodent studies usually don't translate well to humans, and this might well fail to translate, too, but for what it's worth it was an unusually simple and clean study, no genetic engineering or exotic behavioral manipulation or psychological interpretation involved.)

A third study found that people who live in areas where the Mediterranean diet (lots of "good" fat, lean protein, grains, vegetables and fruit, little saturated fat) is prevalent tend to keep weight off as they get older better than people in other areas--but (hallelujah!) the researchers and even (at least in this particular Reuters article) the reporter prominently note that it may well be behavioral and other environmental issues common to people who live on this diet that does the trick rather than the diet itself. The last study predicts US obesity rates have not peaked at about a third as other experts have claimed, and will continue to rise to hit 42 percent--and add that part of the problem is that hanging around with obese people tends to make it more likely that a person will herself become obese, so that the higher the obesity rate goes the more it increases the chance that it will rise further (up to a certain point).

I find all of these studies interesting in their own right, but the main reason I mention them is that all four highlight behavioral and environmental issues as being key to obesity rather than--or at least in addition to--the choice-of-food-types and the genetic issues that are often emphasized in studies. I hope I'm seeing a trend here. We can't get rolling on solving the obesity problem until we stop fixating on poorly understood physiological processes and on molecular biological factors that we can't do anything about, and start focusing on behavioral and environmental changes that we can start working on today. That's what got us into this fix, and that's what will get us out.

Is it all about the calories?

noreply@blogger.com (David H. Freedman) — Sun, 31 Oct 2010 22:04:00 +0000

Does which foods you eat matter in weight loss? I don't think any aspect of obesity and weight loss is more confusing, or more responsible for people's muddled thinking and poor choices in approaches to taking and keeping weight off. Most of the answers we're given to this question fall roughly into what seem like two sharply contrasting camps. The "it's all about the calories" camp (be warned, this link brings to you a nasty little article) suggests it doesn't really matter what you eat, you just need to eat small-enough amounts of it to not exceed the calories you're burning. The "eat healthier foods" camp suggests that you will lose weight if you emphasize certain foods over others--some push fruits and vegetables, others "less-processed" foods, others less-calorie-dense foods, others low carbs, others low fat, and so forth.

Here's my take on it. (I've been interviewing many, many respected experts in the obesity field and reading quite a lot of studies and articles, so I'm not entirely shooting from the hip here, or at least not more than anyone else. Consider this a synthesis of what I've been finding out.) The bottom line is that both camps are sort of right, but they're both a little misleading, too. It's true, you can lose weight eating anything if you keep portions small enough, and you can gain wait eating only vegetables if you eat enough of them. But most people are indeed more likely to keep the weight off if they lose it by emphasizing certain types of foods. That's because some foods more than others tend to push the various physiological and perhaps psychological buttons that will make it harder for you to keep control of your calorie intake. In the end, you'll still have to take in fewer calories than you're burning--but most people will find it easier to do that with some menus than with others.

So which foods should the would-be weight loser emphasize? There's a certain amount of disagreement on this question, to be sure, but a rough consensus of evidence and expert opinion favors cutting down significantly on sugar and refined carbs (like non-whole-wheat bread and pasta), taking it easy on fats (especially saturated fat, for other health reasons), eating good amounts of relatively lean protein (especially fish, chicken, and soy, prepared without much oil or butter, but beans, wheat gluten, egg whites, whey and pork can be good sources of lean protein, too), and eating lots of vegetables and reasonable amounts of fruit and other foods high in fiber. Most experts don't advocate ultra-low-carb diets (or even counsel cutting down much on complex carbs like whole-wheat foods), and most don't think an ultra-low-fat diet is worth the trouble. There are three main weight-control benefits to these recommended foods: They tend to be less calorie-dense, so they feel more filling per calorie and it's easier to meter how many calories you're taking in compared to a small, dense calorie-bomb like a piece of candy or fried chicken; they're less intensely stimulating to your pleasure systems, so you'll be less likely to feel compelled to pig out on them; and they tend to enter the bloodstream at reasonable rates, avoiding the blood-sugar spike-and-plummet effect you get from eating simple carbs that can lead to intense appetite swings.

Now having said all this, I'd like to point out that while eating "healthier" foods is a helpful and for most people important element of keeping weight off, I don't think it's necessarily the most important element, and it's absolutely not the only element, as is often implied by some weight-loss gurus. Most people will not be able to keep much if any weight off just by trying to take in more healthy food, if everything else they do and everything else that's going on around them otherwise remains the same. For most people keeping weight off requires a full-court press via a "behavioral" approach, something I'll be talking a lot about here and elsewhere. Part of that approach also involves finding out which healthier foods work best for you in terms of being as satisfying as possible without pushing your appetite and cravings buttons. And it also involves being smart about the way you introduce these foods into your daily menu and make enjoyable habits out of eating them, and about how you regulate your intake of these healthier foods as well as of those less-healthy foods you may also want to take in in order to have a satisfying diet.

Does all this seem like a lot of work to figure out, put into action and maintain? Well, it can be, but if you get good guidance it shouldn't be all that hard. Even if it is a lot of work, the benefits people get out of losing excess weight in terms of their health and how they feel almost always seem worth the trouble. And if you do the behavioral approach right, losing and keeping off weight--especially if you lose it slowly, and try don't lose a large percentage of your body weight--need never be hugely demanding or uncomfortable, and in fact ought to be highly satisfying and in many ways enjoyable.

Oh, behave!--and lose weight doing it, says JAMA study

noreply@blogger.com (David H. Freedman) — Thu, 28 Oct 2010 05:40:00 +0000

The Journal of the American Medical Association just published a two-year diet study that I think is well worth looking at--and please remember it the next time you read about how the seriously overweight can't lose weight and keep it off without bariatric surgery or drugs because they're programmed by their genes to be obese. What I especially liked about this study was that rather than focusing on gimmicky diets that call for nearly altogether cutting out some food group (e.g. carbs or fat), or loading up on some type of food (e.g. dairy, as pushed in another recently published study getting some press), or pushing significant calorie deprivation, it instead focused on a "behavioral" approach--that is, in educating participants in how to establish healthier, sensible, sustainable eating and exercise habits, and in providing ongoing support to encourage them to stick with the program. It was also a randomized controlled trial--the obese women who participated were randomly assigned to a "normal care" group that got fairly minimal support, or one of two groups that got much higher levels of support as follows:

The diet component of the program consisted of a nutritionally adequate, low-fat (20%-30% of energy), reduced-energy diet (typically 1200-2000 kcal/d) that included prepackaged prepared food items with increased amounts of vegetables and fruits to reduce the energy density of the diet. The approach was tailored so that participants could choose regular foods when preferred. Participants were encouraged during the initial period to follow a menu plan with prepackaged foods, which would provide 42% to 68% of energy for those who choose not to deviate from the plan. Regular foods, such as vegetables, fruit, cereal or grain products, low-fat dairy products, lean meat or the equivalent, and unsaturated fat sources were recommended to achieve the total prescribed energy intake. Over time, participants were transitioned to a meal plan based mainly on food not provided by the commercial program, although participants could choose to include 1 prepackaged meal per day during weight loss maintenance. Prepared foods and counselors were provided by Jenny Craig Inc (Carlsbad, California).

Increased physical activity was another program component; the goal was 30 minutes of physical activity on 5 or more days per week. Program material and counseling addressed attitudes about weight, food, and physical activity and included recipes and guidance for eating in restaurants, CDs and DVDs to increase physical activity, and online tools and support.

And what do you know, the participants who got the real treatments took off weight and by the end of the two years had kept it off.

By study end, more than half in either intervention group....had a weight loss of at least 5% compared with 29%...of usual care participants.... More than twice the proportion of participants in the center-based and telephone-based intervention groups compared with participants in the usual care group...had a weight loss of 10% or more of baseline weight at 24 months....

As with all diet studies, there's plenty to be wary of, too. It was funded (but not run) by for-profit weight-loss-program company Jenny Craig, which also supplied pre-packaged meals for the studies, and bias toward the funders may well have crept in there somewhere. Two years is typically taken as a standard for proof that a diet intervention helps keep weight off, but obviously it doesn't necessarily tell you how the participants will fare in the next two, or ten or forty years, and weight-losers, like smokers, need to be in it for the long haul in order to really raise their chances of having a long, healthy life, not just long enough to look good for their high-school reunion. The reliance on free pre-packaged food is a somewhat unrealistic model for the real world--though not completely unrealistic if we as a nation start getting more serious, as we should, about helping the obese get healthier. The treatment participants got $25 for showing up for clinic visits--getting paid to lose weight is a hot idea these days, but I don't think smallish payments make a big difference over the long term and fear it just confuses the issue. As the study authors themselves point out, one always has to wonder if the people who participate in a diet study are representative of the population, for example in terms of level of motivation and commitment. But on the whole, I thought the diet interventions were smart, and doable on a large scale in the real world, and it was great to see them produce these impressive results in what seems a relatively careful study.

It also didn't surprise me in the least--behavioral approaches to weight loss, including Weight Watchers, have been doing pretty well in studies on a fairly consistent basis for decades, unlike most other approaches. So let's support more people who need to lose weight to be healthy in eschewing gimmicky and unsustainable diets, and in ignoring the toxic claims that they're genetically incapable of benefiting from any non-surgical, non-pharmaceutical intervention, and instead make it easier for them to get access to comprehensive behaviorally oriented weight-loss programs designed to take modest amounts of weight off gradually, comfortably and forever.

Doctors and dieting; and measuring calorie burn

noreply@blogger.com (David H. Freedman) — Tue, 26 Oct 2010 23:19:00 +0000

Nicholas Bakalar has a good article about physicians' efforts to encourage patient weight loss in the New York Times "Science Times" section. Bakalar is one of the most careful writers at the Times when it comes to avoiding flashy medical findings that aren't likely to hold up, as well in making a point of looking for and clearly reporting on the limitations of the studies he covers. You wouldn't think those would be unusual traits in science journalists, and especially in Times reporters, but they are. (I should also mention I've met Bakalar a few times and consider him a friend, but my admiration for his work pre-dates my knowing him.)

Bakalar's piece makes two important points: physicians normally have little luck in getting patients to lose weight, and physicians tend to have more impact when instead of trying to push a patient into losing weight they instead work with the patient to try to figure out together what to do about the problem. I've been researching both of these issues for my ongoing obesity projects, and Bakalar's article is spot on with regard to both of them. I've asked dozens of physicians how many patients they've managed to convince to lose weight, and the answer is pretty much always just about zero. And the idea of working with patients to come up with an appropriate plan that focuses in part on helping patients to recognize and deal with their lack of motivation, and in part in figuring out what actions can be taken that are realistic for whatever level of motivation they have, is a critical part of a behavioral approach to weight loss. Something I'll be saying a lot more about in this blog and elsewhere is the fact that the behavioral approach, while backed by a lot of evidence, made famous by Weight Watchers and pushed by many highly credible experts and public health officials, is largely ignored by most of the overweight public as well as by most physicians and obesity researchers--and I think it's a big reason we keep getting bigger.

Separately, here's a piece, this one in Canada's Globe and Mail, that hits on a another point I've become very interested in: the terrible job that people and devices do in measuring calories burned when exercising. I'll have more to say about this soon.

Should the public be told about the trouble with medical research?

noreply@blogger.com (David H. Freedman) — Tue, 26 Oct 2010 03:09:00 +0000

Among the reaction to my Atlantic article there has of course been a certain amount of skepticism and criticism. Some of the criticism has been perfectly fair and insightful, pointing out the ways in which I or Ioannidis (the physician-researcher I profile in the article who has documented and analyzed the high wrongness rate in medical research) might ourselves be biased, and might be spinning some aspects of the story. I touch on this problem in the article, and have a whole chapter on it in the book, and I have no interest in denying that my own bias and sloppiness (as well as those of the people I interview and those of my editors) may skew things.

I generally welcome criticism, and usually don't respond to it--I figured I had my say--except as part of a formal response to comments submitted to the publication that ran the article. But I saw a blog post today that I think calls for a bit of a response. The post, by the physician-researcher David Gorski (whom I actually briefly quote in the Atlantic article), echoes posts in other blogs from a few people in or close to the medical community in essentially suggesting that the problems with research that Ioannidis has uncovered and that I report on in the article aren't really big problems; rather, they're just an acceptable part of the nature of research. I don't think so. Bias and sloppiness may be routine and perhaps inevitable even among top researchers, but that doesn't mean we shouldn't be made aware of the extent of the problems and the toll it takes on the credibility of medical findings--and the vast majority of researchers seem to agree, to judge by most of what has been posted in response to the article. Gorski's post also states that we should focus on the fact that (as I report in the article) 90 percent of large randomized controlled trials tend to hold up, and not pay much attention to the fact that other types of studies sink to levels as low 10 percent rightness and even lower. This is to me a shocking argument, considering that large RCTs make up a tiny percentage of the studies that fill journals, make headlines and influence treatment and lifestyle decisions.

Finally, the post argues that everyone should put their energy not into looking into the problems with mainstream medical research, but rather into the poor or non-existent science behind alternative medicine--and that we should keep our mouths shut about whatever problems we do find with mainstream medicine because it only gives ammunition to the alternative medicine crowd. Once again, I have to strongly disagree. People who are drawn to alternative medicine have already proven themselves essentially either uninterested in or incapable of assessing scientific evidence, and when researchers like Gorski rant and rave about alternative medicine they're really just preaching to the choir, as is clear from the comments that appear under his post. In fact, compare the nearly unanimous point of view in these comments to those that appear almost anywhere else in response to the Atlantic article--Gorski's fans clearly have their minds made up about people who criticize mainstream medical research, and they don't even actually have to read the criticism themselves to feel comfortable commenting dismissively and authoritatively on it. Some of the comments, following Gorski's lead, include ad hominem attacks on me that are based entirely on sloppy and mostly incorrect assumptions about my background.

Unlike the well-known absence (with a few exceptions) of good science behind alternative medicine, the serious problems with mainstream medical research have largely been unknown outside of the medical community itself. I believe the public has a right to hear about them, and to judge by the reaction the public seems quite interested in hearing about them. I quote Ioannidis in the article as pointing out that if mainstream medical science tries to keep quiet about its problems and limitations, then it is doing what it accuses alternative medicine of doing--misleading the public. I'm glad Gorski and his fans represent a small minority of the medical community in being unwilling to own up to and communicate these problems--see, for example, what the British Medical Journal had to say about my book--and in focusing instead on endlessly recycling the same old complaints about alternative medicine because it makes them look good in comparison.

And for the record: Along the way, Gorski belches out the sarcasm-and-bile-drenched claim that my earlier post on this blog relating to quack autism researcher Andrew Wakefield reflects my refusal to recognize that Wakefield was wrong. That's just plain silly. The point of the post was that the outing of a rare, gross fraud like Wakefield distracts from the more widespread, routine problems in medical research trustworthiness. I think I was pretty clear about that, but judge for yourself. I happen to be a little sensitive to the suggestion that I support quack autism research, because two members of my immediate family work with children with autism, relying solely on the treatment that is the mainstream standard of care, applied behavior analysis. I know quite a bit about autism quackery, actually. I just didn't think the intelligent readers of this blog needed me to rant and rave, Gorski-style, about an obvious and blatant charlatan who had long been making global headlines for his misdeeds. (And my Wakefield post linked to an article that described the misdeeds at length, though I just now changed the link to point to a similar article because the original is no longer online.) Considering that he passes himself off as the champion of objectivity, facts and reason, Gorski seems surprisingly comfortable distorting the facts to fit his nearly undisguised biases. But maybe we should be grateful for undisguised biases--it's really the well-disguised ones we need to watch out for.

I blab about medical wrongness on MSNBC

noreply@blogger.com (David H. Freedman) — Fri, 22 Oct 2010 02:22:00 +0000

Medical Wrongness in The Atlantic (and a few notes)

noreply@blogger.com (David H. Freedman) — Sat, 16 Oct 2010 13:56:00 +0000

I have a big feature article in the new (November) issue of The Atlantic, which just came out. It's the magazine's annual look at "Brave Thinkers," and it leads off with my longish profile of Dr. John Ioannidis, who has spent most of his career studying and exposing the many problems with published medical research. My book Wrong opens with Ioannidis, and comes back to him a few times. But in the article I go much deeper into his work, his background, his personality and his thinking--I spent several days with him in Greece for the article--and say more about what his discoveries mean for medicine and doctors' ability to treat us effectively. It's not a pretty picture. Think of the article as an extremely long, important and (I'd like to think) colorful post for this blog.

By the way, sorry for the long gap since the last post, I got caught in an extended perfect storm of article deadlines, and travel for research and speaking engagements. (And it's not over yet.)

Meanwhile, on another semi-personal note that affects this blog, I've been transitioning to some new projects. I'll say more about these projects in the coming months, but for now let me just say I have a new special interest in obesity and weight loss, which I (and many others) think have become the biggest single health threat to the length and quality of our lives that is also potentially fixable. The blog's basic theme isn't really changing, but a lot of the posts will be about issues relating to obesity and weight loss. Note that I've parenthetically added the new special interest in obesity to the blog's title. I hope it goes without saying I'd love to get feedback from MSOMed readers on this partial change in focus.

Diet Secret Revealed by Scientific Study! (Gulp)

noreply@blogger.com (David H. Freedman) — Tue, 24 Aug 2010 14:44:00 +0000

A new study getting some very prominent and excited press, including a big feature spot on the Today show this morning, has found that drinking two glasses of water before a meal is the secret to losing weight. The Today show and the articles have noted that the study was a randomized controlled trial, which as we all know is the gold standard of medical research. So get ready to guzzle the H2O, and finally lose those pounds!

Or maybe not. Diet studies are terrible, and for a number of reasons. They're of course subject to all the same problems that all medical studies suffer from: poor design, bad measurement, researcher and subject bias, patient selection problems, poor analysis, and more. Randomized controlled trials--in which, in the simplest case, subjects are randomly divided into two groups, one of which gets a special treatment and the other doesn't--can help with some of these problems, because in theory whatever mistakes are made or biases take hold in the study with one group, the same should apply to the other group, so any differences in the results with the two groups should be the real deal. Well, it doesn't always work out that way, even when an "RCT" is done right. But in this case, as with most diet studies that claim to be RCTs, it wasn't done even close to right. The really big advantage to RCTs, as I wrote in my last post, comes from their being "blind," meaning that both researchers and subjects ("double blind" is the technical term) don't know which subjects are in which group. That's what really has at least a shot at eliminating biases. But you can't blind diet studies, because, for example, you can't fool people into thinking they've just drunk two glasses of water when they haven't, or vice-versa. And that means that the researchers and subjects are free to be very biased toward the treatment under study. They all want the research to pan out, and they tend to find ways to make sure it does. It's also questionable whether non-blind randomized studies are truly randomized. The problem here is that once people in the study are subjected to the different treatments, you can start getting very different drop-out rates in the two groups, sometimes right up front. If you agreed to be in a study of some great new diet technique, and then were immediately told you're going to be put on a plain old diet without getting to even try the technique, wouldn't you be more tempted to just blow it off? After all, you've been on diets, they didn't work--why bother trying again with the same old thing? The researchers are probably hoping you'll fail on it so that their technique will prove effective, and they may communicate discouragement. It's a mess of a study set-up.

It gets worse. Diet studies rarely go on long enough to determine whether people actually keep the weight off, which as we all know is the real question. People tend to lose weight on almost any kind of diet, typically over a period of a few months--but then they gain it all back, and often more, over the next year or so. This water-drinking study as originally published some months ago went on for 12 weeks, a classic set-up for misleadingly concluding that the diet was effective. But here's where things get interesting. Though the original study only lasted 12 weeks, the newly released findings have the researchers claiming in public statements that the water-drinkers in the study on average kept the weight off for a year, and even lost a bit more. This is an extraordinary claim that sets off all sorts of alarm bells for me. Careful diet studies almost never report that sort of longer-term weight-loss success. And while the water-drinkers reportedly lost and kept off an average of 17 pounds after a year, the non-water-drinkers in the study lost and kept off an average of nine pounds after a year. Frankly, I'm more impressed by the non-water-drinking results--it's even more unusual for the non-gimmicked dieters in a study to keep weight off that long. In looking at the original 12-week study, I didn't see any specifics about what, if anything, the researchers did (or reasonably could have done, for that matter) to ensure that the subjects in the groups dieted in a way resembling the way people typically diet, that they didn't receive some special encouragement or coaching, that the two groups were treated identically by researchers, that the groups accurately reported what they were eating and drinking, that the water-drinking group really drank the right amount of water before eating and that the non-water-drinking group didn't drink a lot before or during meals. It also wasn't clear what special pains, if any, were taken to make sure that bias wasn't introduced by drop-outs, or by people who didn't comply with the instructions or accurately report data. (It has been shown again and again that inaccurate self-reporting, which is a problem in many health studies, is particularly egregious in diet studies.) Whatever problems crept into the 12-week study, I can't imagine it was anywhere but downhill in extending it to a year. The researchers certainly sound in the original report like they were trying to be careful, but there's really only so much researchers can do, and the result in most diet studies is that there are potential holes big enough to drive a car through. And that certainly seems like the case with this study. I can't help noting that the authors are releasing these newer findings before they have been peer-reviewed. Now, I've written at some length elsewhere that the peer review process isn't nearly the guarantee of quality that it is often taken to be by the public and by journalists. But non-peer-reviewed data is generally considered one step up from fairy tales in the research community, and I wonder if the claims of this study might change after peer review.

But you don't have to accept any of my reasoning about why this, or any other diet study, is likely to be fairly useless in telling you what's going to help you or anyone else lose weight. Here's a better reason to reject these studies: Scientific studies have found that anything is the secret to losing weight, including low carbs, high carbs, low fat, high fat, big breakfasts, small breakfasts, lots of veggies, lots of fruits, lots of nuts, snacking, not snacking, and on and on--and scientific studies have also found that every one of these gimmicks doesn't work, including drinking a lot of water. There's only one reasonable explanation for these conflicting findings: the scientific studies just aren't very reliable. They fail to shine any light on the problem. We don't have to agree on why that's the case, but it's hard to argue it isn't the case.

It's easy to explain why the water-drinking trick doesn't work in the real world. It's a type of diet I call a "sickening" diet. These diet gimmicks work by making you physically uncomfortable in some way, with the result that your appetite is dulled, as usually happens when you don't feel great. Any diet that forces you to eat or drink a large amount of some type of not-especially-appealing food or beverage will have this effect. Some people don't feel well even when eating low carb or low fat, which helps to explain why these diets may help many lose weight initially. The way the water throws your appetite off is obvious: it fills your stomach, and then when you add food on top of it you get an uncomfortably full sensation. None of these sickening diets are especially effective in the real world for what should be an obvious reason: people get sick of sickening themselves. They don't like it. They don't want to cram in another grapefruit, or celery stalk, or glass of olive oil, or chunk of meat. Go ahead, try the two glasses of water trick. Let me know how long you go before you find yourself staring at those two glasses of pre-dinner water and feeling, perhaps even with a touch of nausea, that the last thing you want to do is force them both down your gullet. Even worse, as the water or other sickening agent becomes more and more repulsive over time, your desire to go back to normal levels of eating (or normal varieties of food, if you've been restricting yourself in some way), will grow, especially as you lose weight, and you'll become hungrier and will experience intense cravings. No wonder people gain it all back and more.

Folks, people have been trying to lose weight by drinking a lot more water for at least four decades. I remember my mother forcing down eight glasses a day in the 1970s under the Stillman diet. She didn't keep the weight off, and neither did most people who have struggled with dieting and tried the water trick. If this silly gimmick worked, you'd have known it a long time ago.

Now having said that, let me say that drinking while dieting is a pretty good idea, as long as we're talking about modest, non-repulsive amounts of water or any low-calorie beverage. It's easy to mistake thirst for hunger, and it's certainly true that having at least a little something in your stomach can temporarily help take the edge your appetite. So sure, step up your water- or tea- or diet-coke-drinking, within reason. Just about every diet expert has been saying that forever, and it very well might help your diet efforts a bit. I'm not surprised the water drinkers in this new study lost and kept off more weight than the non-drinkers. I'm just highly skeptical of the claim that it makes a big difference, and especially of the claim that it can make the difference between your dieting successfully or not over the long term. The researchers (and especially the mass-media reports) seem to believe that it will, but I don't think that belief is anywhere close to being supported by the study. If you're tempted to believe it, then I sincerely wish you the best of luck in getting yourself to stuff down two full glasses of water before sitting down to every meal you take in for the rest of your life, and in restricting how much you eat at all of these meals because of it.

Should You Bypass Obesity-Related Stomach Surgery?

noreply@blogger.com (David H. Freedman) — Sun, 15 Aug 2010 20:23:00 +0000

The latest option for losing weight via surgically reducing stomach size: Having most of your stomach cut away and taken out by a procedure performed mostly through your mouth and down your throat. (A bit of the work is done through small slits in your abdomen.) What little is left of the stomach is then stitched up to form a mini-stomach, with the obvious result that it only takes a relatively small amount of food to fill it up. Other, more-established options for stomach surgery include the gastric bypass, a more extensive procedure in which in addition to the stomach being downsized it is also reconnected to a shorter span of intestine, cutting down on calorie absorption, and the lap band, in which much of your stomach is squeezed off by an adjustable band.

These procedures are often discussed as if they have been proven safe and effective in studies. But keep some points in mind when considering how "proven" a surgical technique is. There are (with a very few exceptions) no good, ethical ways to conduct randomized, blind trials of surgical procedures. It would be hard enough to do the randomization, in which patients are (to oversimplify a bit) randomly assigned to either a group that will receive the surgical procedure or a group that will not, because not many patients are willing to have surgical decisions made for them by the toss of a coin. But even if that issue were overcome, the real problem would be with blinding, which means patients don't know which group they're in. It's not easy to get people to not know whether they've had surgery or not--and even if you could pull it off it's even tougher to do it in a way that doesn't run afoul of ethical considerations. (It's been attempted, believe it or not, but hell was raised.) The result is that studies of newer surgical procedures are mostly observational studies, which means doctors just note how patients seem to be doing. (I'm not counting animal studies. Neither should you. No matter what researchers say, on average these studies don't translate well to humans.) Some procedures that have been widely performed for many years get "case control" (epidemiological) studies, which look back at groups of patients who have received the treatment and compare them to groups who have not. While you can't fully tell how trustworthy a study is just by noting what type of study it is--it's wise to consider all medical studies at least potentially somewhat untrustworthy--as a rough generalization randomized, blind trials tend to be more trustworthy than case-control studies, and observational studies are the bottom of the barrel, though to be sure there are lots of exceptions and qualifications to this pecking order.

In short, the fact that gastric bypass, and, to a lesser extent, lap band procedures, have been found in case-control studies and many observational studies to be fairly safe and effective should not be taken very seriously. These types of studies can be subject to intense biases on both the parts of doctors and patients--they generally want the procedures to succeed, and may distort their observations and do a poor job of recording all relevant data. Researchers also typically don't have access to all the data they need to fully analyze the situation. (For example, in the New England Journal of Medicine article I reference just above, the authors to their credit note that the study ignores the possibilities--likelihoods, I'd reckon, though the authors beg to differ--that people who had the surgery got much more or better medical attention afterward than other obese people get, and that they may have been healthier to begin with.) The procedures are a huge money-maker for surgeons, and the patients are often desperate to lose the weight and may be eager to convince themselves and others that they've done the right thing and that things are going to work out well. These biases, which can be and often are devastating to the reliability of medical studies, are exactly what randomized, blind studies attempt (if not always successfully) to eliminate. That's why many surgical procedures are widely accepted as safe and effective, only to eventually prove themselves not so safe and/or less effective than other, less invasive and less risky treatments--the list includes many types of heart-related operations, back-pain-related operations, brain surgeries, and on and on.

This newest stomach-reduction procedure has been performed on one person so far. And yet surgeons just about everywhere will soon be able to perform it on anyone they deem suitable, providing nothing obviously terrible happens immediately to this one patient as a result. True, these sorts of "laparoscopic" (performed through small incisions and/or through the mouth, using a tiny camera and light to allow the surgeon to see what's going on in there) procedures tend on average to be less risky than conventional, large-incision versions of the same surgery, but there can be reasons why they are sometimes less safe and/or less effective in some ways--for example, the restricted access and vision may result in a sloppier job of cutting or stitching, or in missing problems with bleeding.

And there are reasons to question whether the people who are getting these procedures really need them enough to justify the risks. (Though the twice-aforementioned NEJM study found that overall death rates went down for obese people who had gastric bypass surgery due to fewer deaths from heart disease, diabetes and cancer--findings that for a number of reasons I suspect may exaggerate the benefits of the procedure--around one percent died from the surgery itself shortly after the operation, and many had complications.) The people who sign up for these operations are typically obese people who have tried to lose the weight through diet and exercise but have failed, and whose health appears to be at some risk. But trying to compare the potential payoff from trying to diet and exercise to the likely benefits of surgery is a bit of a fixed contest. I've been studying the question of why people fail with diets and exercise, and it's clear that the success rates would likely be much, much higher if overweight people weren't getting such almost uniformly terrible advice about how to diet and exercise, and if their motivation to lose weight through dieting and exercise weren't on average so low. Why is their motivation often so low? For one thing, they keep hearing from many researchers and obesity experts that they'll probably fail with diet and exercise, and for another they've been led to believe that surgery provides a much easier and surer option that will provide all the same benefits of a successful diet and exercise program without any of the work--these procedures essentially are intensely marketed much the way cosmetic surgery is hawked, because they're similarly ridiculously profitable. (Another issue is whether the success rate for dieting and exercising is really anywhere near as low as we've been told--but that's a more complicated story.) Meanwhile, the success and benefits of surgical weight-loss keep getting pumped up through studies that are likely somewhat biased and otherwise flawed.

I don't doubt there are obese people who, when the whole picture is soberly assessed, might be making a reasonable decision to undergo one of the procedures. But I suspect it's a fraction of the number of people who are actually getting the surgeries. I was especially appalled to see a big and very well-researched and well-written cover story in the Atlantic earlier this year on the subject of obesity essentially advocate for, or at least seriously suggest the idea of, the government putting its anti-obesity money into handing out gastric bypass surgery for the obese, presumably instead of into research, education, good-nutrition programs, more-exercise initiatives and other anti-obesity public-health initiatives. The article, which for sure in many ways was terrific, more or less declared dieting and exercise to be a waste of time--a point of view which is pushed by many published medical studies relying on highly biased and flawed set-ups (as evidenced, for example, by the fact that findings from these studies widely and sometimes sharply conflict), but which flies in the face of the significant documented success rates that hundreds of real-world programs have achieved with obese people (and which has also been backed up by other published studies, for what it's worth).

I think this sort of give-up-on-dieting-and-exercise-and-hold-out-for-surgery(-or-a-pill) thinking is dangerous, and is in fact a contributing factor to the obesity epidemic. If you're thinking of getting some form of stomach-reduction surgery, I'd urge you to do some more research into the possible complications and into dieting and exercising options, and to discuss what you find with your doctor. And if your doctor is pushing you toward the surgery and especially if he seems biased toward it, try a second opinion from a doctor you have good reason to believe has an objective view about both diet-and-exercise programs and surgical alternatives. Many, many obese people have shed the weight and kept it off through dieting and exercise. Shouldn't you be absolutely sure you've given dieting and exercise your very best shot under the right program before you have one or even two of your major organs hacked up and extensively rejiggered?

Can Pregnant Moms Program Babies for Obesity?

noreply@blogger.com (David H. Freedman) — Thu, 15 Jul 2010 02:32:00 +0000

A new study claims it shows that the children of pregnant mothers who put on lots of weight are much more likely to be obese years later than the children of mothers who don't put on as much weight in pregnancy. The announcement of the findings has triggered comments from other researchers and experts suggesting that this study is simply the latest in a series of studies supporting the notion that women who eat too much during pregnancy are placing their children at greater risk of obesity.

Nope. This new study tells us very little, and none of the others tells us much, either. The only sort of study that would have at least a small chance of giving us some real insight into the effect of eating during pregnancy on children's lifelong tendency toward obesity would be one that randomly assigned many, many pregnant women to either a group that was somehow made to put on a relatively large amount of weight during the pregnancy, or a group that was somehow made to put on a relatively small amount of weight. Then the study would have to follow the weight gain of the children in the two groups for a few decades. Such a study would still be plagued with potential confounders, since, for example, it wouldn't be blinded (the women and the researchers would likely know which group each woman was in), and the two groups of mothers might start behaving very differently from one another because of the particular way in which their weight had been controlled. But it doesn't matter, because no one is likely to do that study--I can't imagine researchers being able to line up enough pregnant women willing to participate, and even if they did that they'd be able to effectively control the two group's weight gains during pregnancy, or even if they could that the whole project would make it through ethics review boards. So all researchers can do is track the weight gain of a bunch of pregnant women, wait to see what happens to their children, and then go back and look for links. This approach almost always leads to utterly unreliable results, because we have no way of knowing what causes what in the resulting observed links, and indeed the links themselves are often merely artifacts of bad data and/or bad analysis.

All these pregnant-weight-gain studies really show at best is that mothers who tend to put on too much weight are more likely to have children who put on too much weight. Not only is that painfully unsurprising, but it's tremendously useless information. It doesn't tell us whether that's happening because of a genetic predisposition for weight loss that gets handed down from parent to child, or because mothers tend to pass healthy or unhealthy eating habits onto their children in some way, or because exposing very young children or possibly even fetuses to excessive intakes of food or to less-healthy foods somehow changes their metabolisms or alters their appetite mechanisms. (That first study's conclusions seem to vaguely imply the latter, for what that's worth, which I think is very little.) The studies give even fewer clues as to what ought to be done about the situation. If it's genetic, there's probably little point in addressing what pregnant mothers eat, which seems wrong. If the mother's eating is programming the child in the womb in some way, then what the mother eats during pregnancy becomes critical--and what and how the child eats after birth is not so important, a conclusion that defies everyday observation and common sense. If the mother's weight gain is "transferred" to the child via the food attitudes and habits that the child picks up from a mother who simply doesn't do a good job of controlling her weight, then genes or what happens during pregnancy is largely irrelevant. I think there's a pretty good chance that what we're seeing here is some combination of the three--genes, changes that take place during pregnancy, and (probably especially) family eating habits passed on to the child later on. But the studies don't help pin any of this down in the least.

So what should pregnant mothers take away from all this? Come on, you know the answer to that. They should eat sensibly (and as per doctor's advice), avoid either excessive or insufficient weight gain during pregnancy (unless the doctor orders otherwise), and most important (in my opinion and in the opinion of most of the many experts I've interviewed on this subject) work hard to transmit generally accepted good eating habits to their children, starting from birth and continuing on through all of childhood. (If your doctor disagrees with that last bit, get a new doctor.) I doubt we'll ever see a study that provides convincing evidence that doing anything else makes sense.

Is Long Life Mostly In the Genes?

noreply@blogger.com (David H. Freedman) — Wed, 07 Jul 2010 14:50:00 +0000

Update: A problem with the study that I describe in this post has surfaced within the scientific community, and has even received mass-media attention. It's a technical problem of exactly the sort I warn about in the post. The only thing that's unusual here is that the problem has been called out prominently.

A new study has shown that living into your nineties and beyond is a matter of having the right genes, according to recent headlines. The technique that the researchers employed to identify the genes of long life is much the same one behind many of the discoveries of links between genes and traits or genes and disorders that we hear about frequently. To oversimplify a bit, the game involves looking at many genes in a large group of people who have some trait in common, and then trying to spot which particular genes turn up more frequently in these folks than in a large group people who don't have the trait.

I recommend not paying much attention to this study, or to most studies that purport to have identified key genes behind some important trait or disorder, and for a few reasons. First of all, this basic gene-linking technique, although an impressive one and getting better, is still beset with a variety of inherent limitations and potential flaws that often lead to simply misidentifying genes as being closely linked to a trait in most people when they are not, and misses many and possibly most of the genes that actually influence the trait. Part of the problem is that the technique is a highly statistical one based on probabilities involving all sorts of manipulations that can leave the picture convoluted and murky. In addition, the very notion that a relatively small number of genes is likely to play a huge role in determining a trait or disease risk is for the most part a mistaken one, or at best a gross oversimplification. Genes act not alone or even as a small band, but rather as a vast orchestra. Even more confusing, genes can be "turned off" so that they might as well not be there, or partly turned on so that they contribute only weakly to a trait or disease risk. What turns genes on and off? Each other, the environment, other molecules in our cells, and strips of DNA that aren't even parts of genes. It gets worse: Genes can appear in single form, or in multiple copies that increase their influence in ways most gene tests don't detect. They can pop out of their slot in the genome, replicate themselves, and then reinsert themselves somewhere else in the genome. They can flip around backwards, which also isn't detected by gene tests, even though a backwards gene can behave differently. Throw in the fact that genes can be changed by viruses, and that any protein made by a particular gene can do different things in different people, or different things in the same person at different times depending on what else is going on in the body, and you've got complexity of such staggering breadth and depth that scientists who are being honest about the situation admit they'll be lucky to make a small dent in the task of sorting it all out in their lifetimes.

Consider: A 2009 study of about 6,000 people came up with a technique for predicting the height of a person based on looking at the 54 genes most closely linked to height. The results turned out to be one-tenth as accurate as averaging the heights of both parents and adjusting for sex, a technique introduced in 1886 by statistician Sir Francis Galton. University College Dublin biomolecular researcher Helen Colhoun and colleagues have estimated that 95 percent of studies that find gene links are just plain wrong. Harvard genetics researcher Joel Hirschhorn and colleagues surveyed the medical literature on 166 published genetic links to illness that were each examined in at least two other published studies, and found that only six of the links--less than four percent--held up in all the studies. John Ioannidis of Tufts University Medical School has calculated the average odds of a gene-link study being right at one out of hundreds, or worse, depending on the disease. In the case of schizophrenia, for example, Ioannidis reckons a one out of 2,000 chance of a gene-link study being right. His estimates suggest you would have almost as good a chance of identifying some types of genuine gene links by throwing darts at a diagram of the relevant sections of the human genome as you would by reading research journals. Researchers claim their hit rate has improved quite a bit in the past few years, but we won't know the extent to which that's true for a while to come. Needless to say, all these substantial uncertainties and vagaries often get swept under the carpet in the reported findings of an exciting new study, and are almost always ignored in the mass-media reports.

None of this is to say that the study in question here didn't correctly identify many genes that may in fact in some cases be potentially important contributors to living a very long life. But even if the claim is largely or at least partly right, it's still a misleading one. When we hear it, we assume that we'll need many or most of these genes to have a good shot at a long, healthy life--and that's an absolutely unwarranted conclusion. People who live extraordinarily long lives need everything to go in their favor, including many things that may be largely irrelevant to those of us who hope to keep decent health "merely" into our 80s. Assuming we need the genes common in people who live to be 100 may be like assuming a good-performing car needs to have the components common to race cars.

Even if it does indeed help quite a bit to have the right genes in order to live a long and healthy life, it also helps to get a lot of other things right. What has come through from all the genetic studies more clearly than anything else is that for most of us genes really don't influence your destiny as much as, or at least any more than, your behavior does. Folks, if you want to live relatively long lives, and perhaps more importantly stay relatively healthy late into that life, there is powerful evidence that eating sensibly, exercising, breathing clean air, avoiding undue stress, and refraining from obviously bad habits such as smoking, heavy drinking and not wearing seatbelts, can for many and possibly most of us trump genes. In fact, for all we know, some of the genes that the very-long-lived had in common in this study were genes that influence healthy behaviors--in which case anyone engaging in the behaviors would get the same benefits, whether they had the genes or not.

Your fate is probably not genetically sealed--it is much more likely that your health is to a large extent under your control. Don't let announcements of marvelous gene-link breakthroughs lead you to abdicate that responsibility.

The Trouble with Medications

noreply@blogger.com (David H. Freedman) — Thu, 01 Jul 2010 16:00:00 +0000

One recent set of headlines noted that an experimental, cutting-edge drug for the difficult-to-treat disease hepatitis C isn't looking good for FDA approval because there's evidence it can harm patients without much helping them. That's terrible news for hepatitis C sufferers, of course, but most of us might just shrug, figuring that's exactly the sort of outcome we might well expect from many and perhaps most unproven, high-tech treatments that are undergoing trials. What the public is much less aware of is that the same dubious benefit-to-risk situation applies to many of the drugs that are already widely prescribed. In just the past few days we've read headlines about how the diabetes drug Avandia, which has been taken by more than a million people, has now been strongly linked by big studies to potentially fatal heart disorders and strokes. And also making the news is a smaller study that suggests testosterone gel--increasingly commonly prescribed to older men to counter some of the debilitating effects of aging, including loss of bone density, muscle mass, mobility, energy and libido--may be strongly linked to heart disorders, at least in much older men with low mobility.

This isn't just some small run of bad luck for the drug world. These sorts of problems are inherent to the very nature of drugs. Our bodies function via chemical "pathways" in which a vast number of proteins made by our genes interact with each other in ways so staggeringly complex that scientists struggle mightily to identify small pieces of the picture. When you take a drug, the hope is that it will go in and interrupt or boost some isolated part of a pathway that's contributing whatever disorder you may be suffering from. But disorders can rarely be neatly pinned down to a simple pathway, which means there isn't a clean target for the drug, which means the drug isn't likely to hit the problem head on. What's more, everyone has different genes, and even when we have the same relevant genes they may be turned "on" or "off" in different ways in different people, so that our pathways our different, which means that even when a drug is somewhat effective in one person it might not be so in another. Even worse, the drug is almost certainly affecting other pathways that are important to our health, with the effects rippling through the body in ways that may well cause harm. These basic problems are why we've seen a stream of much-hyped, widely used drugs yanked from the market after years, leaving behind a trail of people who weren't much helped, or of people who suffered or even died from the drugs. Vioxx is probably the best-known example from the past several years, but recent headlines have listed many others.

Indeed, it would be miraculous if a drug could go in, completely solve a problem, and do nothing else--virtually no drugs have ever been found that pull that trick off. Instead, the vast majority of our drugs have much messier effects on us: they sort of help some people, hurt others, and don't do much of anything for yet others. Even established, major drugs don't work on 40% to 75% of people, according to a 2005 review paper in The New England Journal of Medicine, and the variation in effectiveness and risk of side-effects tends to be much greater for newer, less-proven drugs. The picture gets even worse when you're talking about patients who are on multiple drugs, which can react with each other in any number of ways that are rarely well understood and often altogether unstudied. We don't get all this from the findings of most studies, because they tend to report averages, and are often presented in a way that make it sound as if a drug can do a lot for you, with only some chance of causing you problems. That may be sort of true, but there's really no way of getting around the fact that for most drugs you're rolling the dice to some extent as to whether the drug is going to help or hurt, if it does anything at all. There's hope genetic tests will eventually boost the odds further in your favor, but right now the claims you hear in the news that this is happening today is mostly hype, with just a few exceptions.

I want to make it clear I am in no way advocating pressuring your doctor to take you off any of your drugs--doctors admit in surveys to often succumbing to patient pressure on some drug decisions even if they don't think the decision is medically best for the patient--and I most certainly don't want anyone stopping drugs on their own. But there's no reason why you shouldn't ask your doctor to explain in more detail how likely a drug is to help, how likely it is to hurt, and why he thinks it's worth it. By the same token, you might want to know what applicable drugs she's decided aren't right for you, and why. Why shouldn't you be involved in a decision that essentially involves placing a bet on risks and benefits to your health? I always bow to my doctor's judgment, but she's willing to explain how she's arrived at it, and she's interested in getting my input when it's a matter of weighing the odds, as is usually the case with medications.

Breakthrough School Anti-Obesity Study Proves...Little?

noreply@blogger.com (David H. Freedman) — Mon, 28 Jun 2010 02:26:00 +0000

If you want a wonderful illustration of the paucity of clear information with which many and possibly most health studies provide us, and in particular how hard it is to wring any sort of credible insight out of weight-loss studies, look no further than the study currently making headlines by claiming that it proved the effectiveness of school programs designed to reduce obesity.

The USA Today report on the study kept it really simple: "The health interventions significantly lowered body mass index (BMI) in children in the 85th percentile or more. Overweight or obese kids in intervention schools were 21% less likely of being obese by the end of 8th grade. The program also lowered average levels of fasting insulin and the number of students with a waist at or over the 90th percentile in intervention schools."

But the HealthDay report provided some additional information: "....The program failed to reduce the overall numbers of overweight and obese schoolchildren--those numbers fell by 4 percent over three years whether the 42 middle schools in the study had such initiatives or not, the researchers report.... [and] children from both types of schools had the same average blood sugar levels and the same percentage of students with elevated blood sugar."

OK, so let's review: The interventions made a big difference with overweight kids--but didn't make the kids much less overweight. And the interventions reduced the risk of diabetes--but didn't prevent the high blood sugar levels that are the main indicator of diabetes or pre-diabetic conditions. Got that?

Here's what apparently happened. The schools that had the interventions saw their initially overweight kids become on average very slightly less overweight over the course of the study--just enough of a drop, it seems, to push many of them from being just heavy enough to be classified as overweight to just missing being heavy enough to be classified as overweight. Voila! Not much reduction in weight (compared to height) for the overweight kids, but a significant drop in the number of them that were "officially" overweight. The interventions did little or nothing to keep kids who weren't initially overweight from becoming overweight. And there was almost no difference between what happened in the schools that had the interventions and the schools that didn't--in both schools, there was a very slight drop over the course of the study in the kids' weight (compared to height).

As for the diabetes risk, the kids in the intervention schools saw slightly lower levels of insulin in their blood, which is generally associated with a lower diabetes risk. But it's a less important indicator than blood sugar levels, which weren't improved in the intervention schools. That's a great example of how scientific findings get muddled and often outright derailed by the choice of what gets measured in a study. (It's a problem I discuss at more length in an article in the July/August 2010 issue of Discover Magazine.)

Aside from the confusing and somewhat misleading way these results were presented in the press release, and made worse in some media accounts--it seems to me an honest presentation would have simply stated up front that the interventions didn't seem to offer any clear evidence that the interventions worked--there were complicating issues in the way the study was conducted. For one thing, the intervention schools not only made changes to the food available to the kids, but it also required longer and more intense physical activity. Yes, most of us (including me) believe these two factors go hand in hand when it comes to reducing obesity. But it may be that one of these factors has a much bigger effect than the other, and it is probably the case that some schools will find it much easier to implement only one, and not the other. So studies need to try to tease these two apart. But the bigger problem, I think, is that the schools that didn't get the official interventions were given money to make whatever changes they felt like making to their nutrition and fitness programs. Who knows what these schools did with the money? We don't even know what we're comparing here.

I certainly believe we have to come up with school-based approaches to reducing the astonishingly high child obesity rates, and I applaud any effort to study how that might be done. Unfortunately, this study's results seem to join the long train of obesity study findings that cast little light on the subject. Presenting the findings in a way that makes it sound as if a marvelous breakthrough was achieved only makes things worse.

Why We Keep Questioning Exercise and 'Healthy' Eating

noreply@blogger.com (David H. Freedman) — Tue, 22 Jun 2010 02:52:00 +0000

Newsflash: Exercise is good for your health. So is cutting down on high-fat meats, and on sugar and refined carbs such as white flour and white rice. Are you surprised? I'm not, personally, but it sounds as if a lot of people out there are finding these notions hard to believe, because we keep seeing health headlines that announce the latest study to discover that following these straightforward and generally well-accepted suggestions lowers the risks of various diseases, and of obesity.

Why do studies keep pounding these points home, when most people who actually care what studies have to say on these questions (as most people in America probably do not) have long since come to believe they've heard enough to make up their minds? Well, for one thing, that's how science is supposed to work--you keep validating theories with new tests, because the new tests may be better than the old ones, and might turn up different answers or at least new twists on them. And the accumulated results from many studies give scientists a much better handle on what's really going on. (The far bigger problem in science is that the vast majority of published research isn't validated at all, but that's a different story.)

Not only that, but the fact of the matter is that every so often an at least fairly credible study turns up evidence that suggests these standard healthy habits may not do as much for us as we'd like to think, and may even hurt. Thus there was the recent scientific review that suggested there is little solid evidence that any of the recommended lifestyle and nutritional habits lower the risk of Alzheimer's, even though we've been hearing that they do for years. There are studies that, in violation of what virtually everyone who has lost weight and kept it off knows, have found that exercise doesn't make any difference in controlling weight, a claim transmitted without doubt or qualification by former U.S. FDA commissioner David Kessler in his best-selling book on obesity. There are studies that find that eating a lot of saturated fat is just fine (these are pushed by the Atkins diet fanatics, of course), and others that conclude people would be thinner and healthier if they loaded up every morning on a high-carb breakfast. More than one study has found that being overweight may help you live longer.

So what's up with all that? Probably several things. First of all, bear in mind that scientists themselves have recognized (as I've documented at length elsewhere) that even most prestigiously published medical research is refuted within a few years. Research is hard enough when done impeccably, but it is in fact plagued with surprising levels of sloppiness, bias, fudging and other distorting shenanigans. So no results should be surprising--someone, somewhere will manage to screw a study up and get exciting but false results that some perfectly good journal will be thrilled to publish. In addition, different researchers who are supposed to be studying the same thing often end up measuring very different things in very different ways, and in very different sorts of people. Thus one study might conclude that a certain diet lowers the risk of, say, diabetes while another concludes it does not--simply because one of the studies measured blood-sugar levels in healthy patients while the other measured deaths from diabetes-related complications in very ill patients. (These measurement mismatches may be part of the problem with the studies that find obesity can be protective--it seems to prove so only for older patients and those with extensive heart disease, perhaps because old or sick people who are thin face greater risks from nutritional shortages than from the slower-acting ravages of obesity, or so it has been speculated.)

But there's an even more basic reason why we shouldn't be surprised that studies conflict on the healthfulness of nutrition and habits. There are thousands of factors that come into play when it comes to the ways various nutrients, habits and other environmental factors affect us, and they interact in a complex web that science may not yet have barely begun to unravel. Scientists try to tease the roles of individual factors out in their studies, but rarely can they honestly claim to have succeeded. (And let's not even get started here on the fact that they often base their claims on animal studies.)

All of these challenges conspire to distort study results and further confuse an already confusing picture. At least with exercise, satured fat and refined carbs there's a reasonably strong consensus of evidence, if not an unblemished one. That's why I'm going to keep exercising, and limiting saturated fat and refined carbs. I'm not fully confident any of that will do much for me, but at least I know I'm playing the odds.

Do Blood-Pressure Pills Cause Cancer?

noreply@blogger.com (David H. Freedman) — Mon, 14 Jun 2010 01:37:00 +0000

Blood-pressure pills appear to be linked to higher risks of cancer, according to a big review study making headlines. Should these results be at least a little worrisome to you if you're on one of these medications? In my opinion, yes--it's worth discussing with your doctor. (Please don't stop taking your pills on your own.) This study has many of the earmarks of more trustworthy research. It's a meta-study, which means it looked at the results from several previous studies, so that if some of the studies were troubled there's still some hope the results from the better studies will partly compensate for those problems. The studies were randomized, controlled trials, which means the people in them were randomly assigned to either take the medication in question or not take it, which can eliminate a lot of the problems studies run into. (I'm oversimplifying, but that's the basic idea.) And the studies were large, totaling some 60,000 patients, so there shouldn't be as big a chance for statistical flukes as there would be in small studies. None of these characteristics guarantee reliable findings, but they can all help.

It's worth noting that some articles describing this new study report that the study found that people on the drugs have a one percent higher risk of getting cancer. But other articles say the findings indicate risks go up on average about 10 percent, and for lung cancer a whopping 25 percent. The seeming contradiction here is due to the media's ongoing, near-complete and deeply problematic failure to specify and make clear the difference between absolute risk and relative risk. When your absolute risk of contracting a disease goes up by, say, ten percent, it means that, for example, if your risk of the disease was 14 percent, it is now 24 percent (14 plus 10), a big difference. When your relative risk goes up by ten percent, then if it was 14 percent, it is now around 15 percent (14 plus ten percent of 14)--not such a big difference. So in this example, an increase in relative risk of about 10 percent translates to an increase in absolute risk of a mere 1 percent. Research institutions typically want the public to be impressed with the importance of their results, so they often emphasize to the press relative risk, which is a generally misleadingly high number. But in this case--perhaps because there is concern that people on blood-pressure pills will overreact and stop taking them--there seems to be more interest than usual in reporting the change in absolute risk, which tends to be a very low number. Assuming you don't carry any special risk factors for lung cancer (such as smoking), you only have a tiny chance of getting it, and if you add on the apparent increased risk from blood-pressure pills, you now have a slightly less-tiny chance of getting lung cancer. Still, your chances of getting cancer of any type aren't so tiny, and a one percent increased absolute risk is nothing to sneer at. A percentage here, a percentage there, and pretty soon you're taking years off your life.

If you read about the study, you might note that even though the study found an increased risk for blood-pressure-pill takers of getting cancer, it didn't find an increased risk of them dying from it. Unfortunately, you shouldn't take this as reassuring. Most cancer studies fail to convincingly link increased risk factors to mortality, usually simply because it tends to take people many years to die of cancer (if they do die from it, that is), and studies usually don't go on long enough to follow people to their graves. (That's another reason, by the way, that researchers love running studies on mice instead of people--they're conveniently short-lived. We humans can be annoyingly enduring, from a medical-research point of view.)

Talk to your doctor about it. It may be that if you were just on the borderline of high blood pressure but have special risks for cancer, she may want you off the pills. But if your doctor feels your risks from uncontrolled high blood pressure outweigh the possible slightly increased risks of cancer turned up by this study, I'd trust him. In the unlikely chance your doctor doesn't know what you're talking about when you ask about this study, I myself would tell him that I'd be happy to sit there and wait while he looked the study up.