Healthy Food & Healthy Living by Dr. Ayala

Study shows liquid calories trick body and mind to overeat

2012-01-25T06:57:00-05:00

A calorie’s a calorie, isn't it? Well, accumulating evidence shows that our body has a hard time registering calories from beverages in the tally towards satiety; unfortunately, these beverage's calories still count in our energy balance. That’s why the extra calories in beverages are just extra—much like items that didn’t go into the budget, but will nevertheless have to be paid for.

There are numerous studies to prove this point; here are just a few:

Nutritionist Barbara Rolls from Penn State served women water, diet soda, regular soda, orange juice, milk or no drink before lunch. Those given caloric beverages consumed about 100 calories more than those given diet soda, water or no beverage at the meal, without significantly affecting satiety ratings.

In the cute jellybean study, researchers gave men and women 450 calories a day of either soda or jellybeans for a month, then switched them for the next month and kept track of total consumption. Candy eaters ate less food -- compensating for the extra calories. Soda drinkers did not, so they ate more calories than usual.

A study by Richard Mattes and Wayne Campbell of Perdue University looked at the effects of food form (solid, semi-solid or liquid) on appetite. Participants consumed either a whole apple, applesauce or apple juice of equivalent caloric value. The apple juice reduced hunger the least, the whole apple reduced hunger the most and the applesauce response was intermediate. The participants that had the beverage apple where ready for their next meal almost an hour earlier than those that had a bitable apple.

Is satiety in our senses or in our heads?

Previous research suggests that a fluid consistency leads to less satiety. Beverages require less chewing, and travel faster through the stomach and the intestine, explaining the lower satiety effect.

But we also eat and get full in our mind. Could it be that it’s our mind that doesn’t see fluids as food, and therefore fails to register beverage’s calories?

To try and tease apart the physiological from the psychological a new study led by Bridget Cassady and published ahead of print in the American Journal of Clinical Nutrition devised an interesting experiment. Fifty-two healthy adults were treated to a pre-lunch “appetizer”, consisting of 10 percent of their daily caloric needs. Each participant experienced 4 different pre-lunch settings, all containing exactly the same amount of calories:

Liquid to liquid: participants consumed a clear, cherry flavored drink. Study administrators demonstrated what happens in the body by mixing the drink with what they called “gastric acid”, but was really ordinary tap water. The mix didn’t change the liquidity of the pre-meal, therefore participants drank a liquid, and believed it remained liquid in their stomach.

Liquid to solid: participants consumed the same clear, cherry flavored drink. Study administrators demonstrated what happens in the body by mixing the drink with what they called “gastric acid”, but this time it was calcium chloride, which formed a solid mass upon mixing, therefore participants drank a liquid, but believed it turned solid in their stomach.

Solid to liquid: Participants consumed cherry flavored gelatin cubes. The study administrator imitated what happens in the stomach by mixing the gelatin cubes with “gastric acid” which in this setting was warm water, which melted the cubes, leading participants to believe that although they swallowed a solid, their stomach experienced a liquid.

Solid to solid: Participants consumed cherry flavored gelatin cubes. The study administrator imitated what happens in the stomach by mixing the gelatin cubes with “gastric acid” which in this setting was cold water, which didn’t affect the cubes’ solidity, leading participants to believe that they swallowed a solid, and their stomach is digesting a solid.

Hunger, fullness and appetite were assessed after each pre-meal, as well as objective measures such as blood glucose, insulin and ghrelin, stomach emptying and intestinal transit time and caloric intake in the meal following the test pre-meals.

And the results:

Liquid meals and perceived liquid meals were followed by greater hunger and less fullness. Participants’ responses to liquid to liquid and solid to liquid pre-meals included: ”this didn’t fill me up at all” and “it hardly feels I ate anything”. On the other hand, the solid meal (solid to solid) and perceived solid meal (liquid to solid) elicited responses such as “ I can’t remember ever being so full” and “it feels like I swallowed a rock”.

Participants ate more (in the post-test meal) when they thought they’re eating liquids – 22 percent more, which amounted to about 160 additional calories.

Stomach emptying and transit time in the colon were faster when taking in liquid or when believing the solid turned into liquid.

Insulin and other hormones signaling satiety had an attenuated rise when consuming liquids. Ghrelin, a hormone, which is suppressed after meals, was less suppressed by the liquid pre-meals.

Thinking about liquids is enough to diminish satiety

This study confirms that liquid calories cause less satiety, and also shows that just thinking about food in liquid form increases not only hunger levels but also measurable physiologic responses such as the rate in which the stomach empties and the levels of hormones that affect appetite.

Why does our body seem oblivious to the calories in drinks? Perhaps it can be explained by looking at human history: Throughout most of human times people ate food when they were hungry, and drank water when they were thirsty. Beverages with calories were rare.

Nowadays, sugary beverages constitute about a fifth of the daily caloric intake and are probably the most ubiquitous food item, available for purchase practically everywhere. These liquids calories don't seem to satisfy hunger and are therefore a source for calories that just sneak up on us.

Dr. Ayala

Full disclosure: I’m vice president of product development for Herbal Water, where we make organic herb-infused waters that have zero calories and no sugar or artificial ingredients. I’m also a pediatrician and have been promoting good nutrition and healthy lifestyle for many years.

Reposted as part of Food Renegate's Fight Back Fridays -- join the food fight!

Study suggests kids prefer more color and variety in their plate

2012-01-18T07:55:00-05:00

Brian Wansink is famous for his work on the psychology of eating and for popularizing terms such as "mindless eating" and "health halos." His research has unveiled some of the many occasions in which environmental cues such as packaging, label claims and plate size influence our eating.

There’s something particularly encouraging about Wansink’s findings. If so much of our eating, overeating and unhealthy eating is driven by nothing more than unconscious, mindless habits, a targeted environmental change can improve our eating without much sacrifice, indeed, almost without individuals having to do a thing.

Plate presentation affects eating

A new study from Wansink’s group, published in the January issue of Acta Paediatrica, and led by Francesca Zampollo looks at how the look of the plate affects kids and adults.

Twenty-three kids and 46 adults were shown full-size photos of 48 different combinations of food on plates that varied by number of items, placement of entrée and organization of the food.

Kids preferred plates with more items and more colors, they liked the entrees placed in the front of the plate, and they liked figurative designs. In fact, kids liked it when their plate had 6 different colors and 7 different foods, while adults preferred a plate with no more than 3 colors and 3 foods. Both kids and adults appreciate a non-crowded plate, with just enough empty space.

More color and more choice

Food marketers have known about kids’ attraction to rainbow design for years I suppose. Take a look at the packaging of foods targeted to kids’ and the recurring pattern is lots of colors, shapes and figurative designs. Minimalism and simplicity aren’t a winning style in kids’ products. So I guess young focus groups have told marketers much the same as the study group told the researchers.

According to this study kids visually prefer a plate with many elements and many choices. It is yet to be proven that they’ll actually eat more readily if such a multiple-choice plate were served, but if that is indeed the case I welcome this finding. All we need in order to achieve 6 colors and 7 choices is to serve several kinds of vegetables and fruit to accompany the entrée – and we don’t even need to chop them into a salad.

Have you noticed how presentation affects you or your kids?

Dr. Ayala

Does soda add belly fat?

2012-01-11T06:30:00-05:00

Do sweet drinks cause belly fat? Fat around abdominal organs is much more active metabolically than the fat under our skin, and poses additional risk for diabetes, heart disease and stroke above and beyond the risk seen with being overweight.

And while fat distribution is influenced by age and genetics a growing body of evidence suggests dietary choices, and especially sugary drinks increase fat accumulation in the worst possible locations of our anatomy.

A study from the University of California at Davis showed that drinking 25 percent of daily calories (which is quite a lot) in fructose for 10 weeks increased triglycerides and cholesterol, caused insulin resistance and belly fat accumulation.

A recent study found that even moderate consumption of sugary drinks led to measurable undesirable effects after just three weeks: Belly fat accumulated, fasting glucose levels and inflammation markers rose, and the lipid profile changed when volunteers drank what amounted to just 1 can of soda a day.

Another study in the journal Obesity, following 800 people, found that drinking sugary drinks was associated with significantly more belly fat and wider waistlines.

A new study in the American Journal of Clinical Nutrition adds to this body of evidence with a rather long-term study, in which a small group of overweight people were assigned to drink cola, skim milk, diet cola or water, while fat distribution and metabolic markers were monitored.

Drinking soda for 6 months

The Danish study involved 47 healthy participants – it’s definitely a small study. The participants drank 1 liter – about 33 ounces -- of regular cola, skim milk, diet soda or water daily, for 6 months.

The total caloric intake didn’t differ between the participants, and all the participants gained just about the same amount of weight (almost 3 pounds).

On the other hand, the amount of fat in the liver, abdominal organs and muscle increased significantly in the regular soda group, while it remained unchanged in the other study groups. (Fat was measured by an MRI technique.)

Blood pressure and triglycerides also rose among the soda drinkers.

The soda belly-fat connection

Why would soda lead to preferential accumulation of belly fat? There’s some evidence that the fructose content of the drink is to blame. The simple sugar fructose is metabolized in our body in a way that promotes fat production, raises triglycerides and affects cholesterol levels. Soda is made with either table sugar, which is 50 percent fructose, or High Fructose Corn Syrup (HFCS), which is about 55 percent fructose. Fructose is absent in milk, diet soda and of course water.

Diet soda was off the hook in this study, but other observational studies have shown that diet soda is linked with obesity, type 2 diabetes and the metabolic syndrome.

Is 33 ounces of soda a lot?

While 1 liter or 33 ounces of soda sound like a lot, the authors, led by Maria Maersk, present an embarrassing comparison to average American intakes. The typical young American (12-29y) drinks 60 ounces of sugary drinks-a-day; the average American guzzles 16. Fast food eateries offer 42-ounce and 64-ounce sodas. Unfortunately, 33-ounces-a-day isn’t out of the realm of what people actually do.

Soda, not beer, might be inducing our belly expansion.

Dr. Ayala

Should we reward kids for eating their veggies?

2012-01-04T07:27:10-05:00

Many parents struggle with getting their kids to eat veggies. A new study in the American Journal of Clinical Nutrition tests a new tactic to getting those veggies in and shows that rewarding kids for tasting a disliked veggie increased both its intake and liking.

I was surprised when I read the title of the study – prizes for healthy eating run contrary to the advice generally dispensed to concerned parents – so let’s read through the study and see what we can learn from it.

Rewards and praise for trying veggies

The study, led by Anna Remington, was conducted in North London, UK, and recruited 3-4-year-olds.

The 149 kids who completed the study were randomly divided into 3 groups:

Tangible rewards - parents offer their kid a small piece of the target veggie for 12 days, and if the kid tastes the piece of veggie he’s rewarded with a sticker.
Social rewards - parents offer their kid a small piece of the target veggie for 12 days, and if the kid tastes the piece of veggie he’s rewarded with praise, such as “brilliant, you’re a great vegetable taster”.
Control group - no daily tasting and no rewards.

The target veggie was picked according to the kid’s initial reaction. The families were presented with 6 veggie options: carrot, cucumber, white cabbage, red pepper, celery and sugar snap peas. After the kid had a taste he ranked the veggies from 1 (most liked) to 6 (least liked). The target veggie for the experiment was each kid’s “4”, giving this veggie an opportunity to either rise or fall in fondness.

And the result: the kids who received the prize ate more of the target veggie and reported liking it better than the controls. This increase in intake and liking persisted over the 3 months of follow-up. The praise group also increased its intake and liking, but less so than the reward group.

Give veggies a chance

This study, and many others, capitalizes on the well-known fact that repeated tasting works. We are creatures of habit, and people -- especially kids -- like what they know. The way to know a veggie is to see it often, know its name, and give it a taste – many times. Studies show that it might take 10 taste exposures to get kids to accept a new food.

Young faces will light up with pleasure when tasting a sweet food for the first time, but foods that are out of the realm of sweet, fatty and salty can be an acquired taste, if given the chance.

To know is to like; to like is to eat. In that respect we parents can really make a huge difference in our kids’ food preferences and habits.

Anything to get a kid eating

So how far would you go to get your kids eating healthy? The issue of rewards for eating is a controversial one, with many experts arguing that rewards -- or any kind of pressure for that matter -- are counterproductive in the long run.

This study suggests that rewards do work, at least for 3 months, and the reward was small enough to perhaps make parents deem it a non-issue.

But whether large or small, is a reward worth considering?

I personally believe that eating behavior shouldn’t be punished or rewarded. After all, eating isn’t a good deed or an achievement. Eating, whether healthful or not, is something one does to fulfill a basic self-interested need.

Kids, I think, are not supposed to be eating for their parent’s satisfaction or praise.

How did we even get to accept that “like” is a requirement for eating good food when hungry? Have marketers convinced us that “lovin it” is a prerequisite?

Family dinner should be simple: Serve a healthy meal, don't serve anything that you don't want your kids to eat, no fuss, no electronics, no need to clean the plate, but a taste is much appreciated. Except it isn't, and many families struggle with how to best feed their kids peacefully and healthfully.

Regardless, the person to be thanked and praised is the provider of the meal – praise the cook, not the eater!

What do you think? Would you try prizes to get your kids eating their veggies?

Dr. Ayala

Are junk-eating friends ruining your diet?

2011-12-28T07:22:00-05:00

I'll be taking a a few weeks off to spend time with my family and travel, and will write infrequenly during this time. Meantime, I'll be reposting some of the more popular posts I’ve written over the past years so that new readers have a chance to catch up. Happy holidays!

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Peer pressure is a pretty powerful force that can both help and impede kids’ choices. No kid is totally immune to peer pressure and that’s why I care a lot about who my kids hang out with—I’m sure most parents do.

Peer behavior influences a wide range of health related behaviors--from smoking to alcohol intake to bike-helmet wearing--and also influences kids' eating patterns. The need to belong and the effect of peers are most pronounced in adolescence.

A study in the journal Appetite set out to see if friendship groups affect teens’ unhealthy snacking behavior. The study looked at the snacking habits of about 750 Dutch teens while mapping out who’s friends with who. It also collected data including the teens’ weight, education level and personal characteristics as well as the availability of high-caloric-density snacks (chips, candy, soda etc.) in those kids’ school canteens and vending machines.

Here are the study’s main findings:

• Teens with friends who ate snacks and drank soft drinks tended to do the same if snacks were available in schools canteens and vending machines. In fact most soft drinks were consumed by teens with friends that drank soft drinks.
• The tendency to conform to friends’ snack habits was stronger for boys and for teens with lower education levels.

• Girls ate more healthfully than boys, and seemed less susceptible to peer pressure to snack unhealthfully.

Chicken or egg?

So which came first? Do teens model their friends when it comes to snacking, or do they pick friends with similar snacking habits? This study can’t really answer that question. Other experimental studies though have shown that people model eating choices and quantities after friends’ patterns. Regardless, herd-like snacking behavior suggests new possibilities for intervention: Create a ripple of better eating within the group and it may grow into a wave that includes the entire cluster of friends.

The effect of vending machines

The presence of junk-for-sale in schools was a critical component of unhealthy snacking group-behavior in this study. In schools that had limited or no junk around, peer influence was less strong. It’s quite obvious that regardless of your friends’ habits, inability to perform the habit in school due to a missing key ingredient—the snack for purchase—gives less opportunity for the habit to spread.

Resisting unhealthy peer-pressure

Although friends affect teens quite a bit, and teens spend fewer hours with their family as they grow older, I’m quite sure that good family relationships, good role-modeling from parents and a high self-esteem are really important in enabling kids to stick to what they know is better for their health.

I don’t know how many parents-to-teen-boys (of which I am one) will appreciate this, but this study does hint that hanging out with the girls can promote better eating. I do love a study that compliments girls. Women tend to make healthier food choices at all stages of life, so having us around is usually a health promoting lifestyle.

Dr. Ayala