Cardio is the sweaty messiah of fat loss.

You have to do cardio if you’re trying to get lean.

Lots of cardio.

So you climb onto the treadmill, crank the incline like you’re preparing for a NASA launch, and start rhythmically thudding forward. On the all-to-real hamster wheel. For thirty minutes. At least. Hoping that, if you repeat this on a daily basis, consistency will eventually sandblast you into a wet marble Adonis glistening under fluorescent gym lights.

Unfortunately, doing cardio to lose fat is like having a kid to save a marriage.

Rarely works the way people want it to. Truth is, you don’t need to do cardio to lose fat. And it seems like, more often than not, cardio ends up being counterproductive for reasons you wouldn’t expect.

I know the previous statement has the power to short-circuit a select few subreddits, but I’ll concede. Slightly.

Because the reason “cardio” became synonymous with “shredded” is actually pretty logical, which is exactly where we’ll start to better understand this booby trap.

Why does everyone think cardio is required to get six-pack pixelated?

Cardio is often recommended for fat loss because, a long time ago, some lab-coated sleuths discovered that triglycerides are the primary fuel source for aerobic respiration. (Hang in there.) Triglycerides are fatty packets of energy driving on the roadways inside you thanks to the food you eat. (Almost every food that passes through your throat can be transformed into triglycerides.) When traffic builds, your body clears the roads by shoving excess triglycerides into storage—specifically into adipose cells.

This is the villain origin story of body fat. Body fat is triglycerides parked in adipose. (And in case you’re new here, I’ll be calling “body fat” adipose from here on out. If this causes distress, please take it up with your frontal lobe.)

As for the machinery? Your muscles can run on different fuels depending on which energy system you’re using. One of the systems available is the aerobic system, and it tends—tends—to favor triglycerides for fuel. So when your aerobic system is active (when you’re undergoing aerobic respiration), your body is probably chewing through triglycerides to move you forward like a mammal late for something it regrets agreeing to. With enough aerobic respiration, your body will burn through the more readily available triglycerides and then be forced to take and use the ones stored in adipose cells. End result? Less squishy stuff crammed into those cells, which equates to less jiggly stuff hanging in your love handles.

Need a dumbed-down metaphor? I got you. Aerobic respiration targets triglycerides the same way arcades in the 1990s targeted quarters. You could walk into Funland with a credit card, a checkbook, maybe even a crisp twenty—perfectly valid forms of currency. But the machines didn’t care. No quarters, no Time Crisis. The system required one very specific input. Your body is similar. It has multiple energetic currencies available. But when you trigger aerobic respiration, you’re targeting a specific one. You’re grabbing the body by the ankles, flipping it upside down, and attempting to shake its adipose into the ether.

This is where cardio re-enters the chat.

Why is everyone cuckoo for cardio?

Cardio is a specific type of exercise that maximizes aerobic respiration, which maximizes triglyceride use, which maximizes the absolution of adipose. In theory. Unfortunately, most people use the word cardio the way toddlers use the word dog. Four legs? Dog. Pants? Dog. Emotional-support ottoman? Also dog. So people do four-minute HIIT meltdowns, wheeze through burpees, flirt with unconsciousness, and proudly announce they “did cardio,” convinced they’ve cracked the adipose vault when they barely brushed the energy system that was supposed to be doing the work.

But that’s a story for another day.

For now, let’s assume you’re actually doing cardio. Real cardio. Steady, rhythmic, aerobically-taxing cardio. Which brings us back to maximization of aerobic respiration, the obliteration of triglycerides, and—supposedly—the best possible setup for getting rid of the gelatinous goo stored inside adipose tissue.

Sounds great.

Case cracked.

Jog forever.

Or until you realize you’ve been undergoing aerobic respiration nonstop since the moment you’ve were born.

Your aerobic system is working right now as you read this sentence in your underwear. (Yes, I see you.) Cardio increases the activation of the aerobic system, but the system itself never fully powers down. It’s always on. Which means your body is constantly chewing through triglycerides to recycle its energy supply and keep the machine known as “Donald” (or whatever your name is) humming along. Put in terms even Shemps can understand: you “burn” fat simply by existing.

You can get a decent estimation of how much energy your body uses on a daily basis by multiplying your bodyweight (in pounds) by thirteen. So if you weigh 180 pounds, your body probably chews through about 2340 calories worth of energetic material every day. (By the way, “calories” aren’t real. They are simply unit of measurement for heat energy, just like “degrees” are a unit of measurement for temperature. Confused? Me too.)

Now, it would be wrong to say triglycerides are the only type of energetic material your body uses under that calorie umbrella. But they’re used far more than most people would guess. Which raises the obvious question:

If you’re burning fat all day long… why don’t you look like it?

Because there’s another variable in the physiological financial equation often ignored: income.

Yes, you’re using triglycerides. Damn near constantly. But you’re also earning them through the food you eat, because food is energetic material your body loves turning into triglycerides whenever the opportunity presents itself. And, much like with real money, the opportunity presents itself when income exceeds expenses. The balance determines how much ends up parked in adipose at the end of the day.

Most people aren’t ripped despite being natural fat-burning machines because they earn more than they spend over time. Your body’s survival expenses are already high. And fairly fixed. Simply existing costs a lot. Which is why fat loss doesn’t require heroic cardio or metabolic theatrics. It just requires a fixed income below regular expenses. Under this condition, your body has no choice but to dip into its savings to pay the bills.

Make no mistake: You don’t need to do cardio to lose fat… but you should still do cardio.

Cardio is great. Not necessarily for fat loss, but for almost everything else. Health. Longevity. Blood pressure. Insulin sensitivity. Not dying early. You know. Trivial stuff. Stuff that clearly matters less than visible abdominal muscles.

Cardio is strength training for your heart. Just like squats make your leg muscles stronger, cardio makes your heart stronger. You should do some kind of cardio. Joint-friendly cardio. If you’re an overweight, middle-aged man who’s been sedentary for the past nine years, pause for a moment before resurrecting your high-school running program. Consider the preparedness of your feet, knees, and hips before you repeatedly bash your bones into concrete. I wince when I see people affluent with adipose jogging on the sidewalk.

Beyond health, cardio does increase your overall expenses. It nudges the equation in favor of fat loss. It helps you shrink adipose tissue more than would otherwise occur. Just not by as much as it feels like it does.

When you finish a cardio session and feel your heartbeat behind your eyes, it’s natural to assume you just chewed through a massive wad of fat.

As if whatever crumb was clinging to your abs surely melted, and a six-pack is now seconds away.

Eh. Not quite.

Professor Google will tell you jogging burns about 100 calories per mile. (For the record, you’ll also burn about 100 calories walking a mile. From a fat-loss standpoint, jogging’s main advantage is finishing faster—which is always a good thing unless you’re in the bedroom. So let’s say you lace up, put on your Sunday best, and jog for 30 minutes at a 10-minute-mile pace. You used to run in high school, right? You can cough up a 10-minute mile, right? Thought so. That’s three miles. Roughly 300 calories burned.

In theory.

Thanks to exercise efficiency, metabolic adaptation, and human biology being quietly vindictive, you probably didn’t burn 300 calories. Some research suggests you only burn 50–75% of the calories you think you do after accounting for exercise-related metabolic adaptations, but I’ll give you the benefit of the doubt and say your bout with breathing difficulties deleted all 300 calories worth of energetic material trapped inside of you. Otherwise you might feel too defeated and never try.

What does 300 calories actually buy you?

Well, one pound of adipose (body fat) is commonly said to “contain” 3500 calories worth of energetic material. Under generous assumptions, pretending every calorie burned came directly from adipose, it would take more than ten 30-minute jogging sessions to lose a single pound of fat.

I’m willing to bet 9 out of 10 people would assume they’d lose more than one pound of fat after two weeks of jogging for 30 minutes every day, which is unfortunate because it’s optimistic.

Most Shemps wouldn’t lose weight after adding casual cardio to their lives because most adults gain weight every year. Not because they’re broken, but because they eat more and move less as life piles on. They discover the wonders of beer in college. The need for sugar-crusted Starbucks to help them cram for final exams. They hang up their cleats and stop playing their favorite sports. They rely on packaged food when their daughter is born because nobody has time to wash dishes anymore. The number on the scale rises in a slow, depressing, linear fashion. In other words, most Shemps live in a moderate energy surplus over time.

(I know I’ve been using a money metaphor throughout this and here’s where it gets a little weird because in real life, most people work themselves into debt. But at the dinner table, most people do the opposite.)

Adding casual cardio to this surplus system can certainly help the upward climb. Cancel out the keg stands and kielbasa. Slow annual upward creep toward metabolic syndrome. But the overall impact of this addition depends on *drumroll* how much energetic material you’re eating. (If you’re surprised, you’re not a great reader.)

The odds of casual cardio producing meaningful fat loss in a timely manner are low when the diet isn’t doing its job. Even though cardio tips the scale in the right direction by increasing expenses, the increase simply isn’t Super Effective! enough to make income a non-factor.

I wish this weren’t true. I wish cardio burned an unfathomable amount of energetic material—an amount physically impossible to ingest. But it doesn’t. When you break it down, casual cardio barely negates the calories inside one of those insect-sized boxes of raisins. Never mind the cupcakes, chips, and “reward food” Shemps start morally bargaining for the moment they begin exercising.

“I ran today. I can have that cupcake.”

You can’t.

Cardio is not powerful enough to ensure fat loss without nutritional awareness, which is somewhat ironic because nutritional awareness is powerful enough to ensure fat loss without cardio.

This doesn’t mean cardio is bad. Or useless. It’s just been wildly miscast. Cardio doesn’t fail fat loss. It just can’t combat the energetic toll of twelve quarter-pounders with cheese. You can run around Funland all day blowing quarters, but if you earn a handsome paycheck at the dinner table, you’re never going to end up in debt.

That’s the mistake.

Cardio is a tool, not a throne.

It can assist fat loss.

But it will never rule it.

Do cardio anyway.

Do it so your blood pressure doesn’t resemble a phone number. Do it so walking up stairs in your 50s doesn’t feel like a medical emergency.

Just don’t ask it to wear a crown it can’t carry.

If you want six-pack abs, you should wear a waist-trimmer belt when you do cardio.

After a thirty-minute jog past the same three mailboxes in your neighborhood, the neoprene corset strangling your midsection will be drenched in a sweat marinade of yesterday’s salami, this morning’s regret, and whatever your body does to gym shorts after mile two — a surefire sign you’ve melted a significant chunk of the fat blanketing your abs…

Or so the story goes.

Unfortunately, if sweating were proof of spot reduction, everyone who’s ever suffered a summer subway ride with swamp ass would be walking around with rock-hard rumps.

I’ll be honest: I have not personally interviewed a scientifically respectable sample size of humid human holes to definitively rule out the existence of swamp-assed people with six-pack-shredded sphincters. But my gut — the one currently not shredded by way of sweat — says I can stand behind my intial conclusion with confidence.

Waist-trimmer belts won’t spot reduce body fat, but they aren’t totally useless. You can still use one to suffocate yourself in shame over ever believing sweat alone was the secret to fat loss. (Don’t actually suffocate yourself. But do feel free to imagine that lady with the bell from Game of Thrones trailing a few steps behind you, ringing it softly.)

You can burn fat from specific zip codes on your body by exercising the muscles directly beneath the area you want to tighten.

Want to lose your belly fat? Do crunches. Want to lose your bat wings? Do triceps extensions. Want to get rid of your sausage fingers? Become a typist.

Or so the story goes.

Unfortunately, if using a muscle melted the fat sitting on top of it like butter on a George Foreman Grill, then fat people wouldn’t have fat faces.

Where do you think your chewing muscles are?

There’s only one scientifically proven way to spot reduce body fat.

And no, it is not “be disciplined” or “drink more celery juice while crying into your Peloton.”

It’s dangerous.

But it works.

Takes a little grit.

(And bloodshed.)

Because you have to use a knife.

Since you, a person with nerve endings and also a sense of self-preservation, are not going to go full Freddy Krueger on your own midsection with a steak knife from the Bed Bath & Beyond that’s now just a Beyond, here’s the actual deal: To lose fat from specific areas of your body, you have to create an energy deficit and cross your fingers like you’re 11 years old hoping Raquel Brown notices you at the school dance.

Your body, that smug little overlord, decides on its own which fat it finds least essential to your survival and torches THAT first — completely unbothered by your opinions on the matter. Could be the fat in your neck. Could be the fat between your toes (you have that, don’t lie). Could be the weird little upholstered situation between your eyebrows that nobody’s ever mentioned to you out of kindness.

No way to know.

No way to nudge.

Like trying to pour out a crumb stuck in a cup of water. You tip the cup, hoping the water-logged carbohydrate flops out first. But it never does. It sinks to the bottom of the cup because it’s obeying the laws of physics, not your fickle feelings.

The physics of fat loss bends the knee to survival, not six-pack abs.

And for whatever caveman-era, sleeping-in-a-cave, outrunning-a-saber-tooth-tiger reason your body has cooked up, it will almost always save the fat tucked in the lower belly and love handles for the bitter, bitter end. You may not be thrilled that your stomach currently resembles a rack of hot dogs rotisserie-ing at a 7-Eleven every time you sit down, but your body? Your body thinks that’s adorable. Your body thinks that’s insurance.

So if you’re shrinking everywhere except the one place you’ve been begging the universe for since the Obama administration, there’s only one move left: keep going. Eventually your body will get around to your trouble zones. Unless, of course, you tried the knife thing, in which case, well. I did warn you, and also, please call someone.

You can make specific areas of your body toned and defined as opposed to big and bulky by lifting a light weight for roughly eleven thousand reps.

Want sculpted shoulders that look like scalloped seashells, the kind mermaids keep their lip gloss in? Grab a pastel-colored, plastic-coated dumbbell (the one your aunt keeps next to her yoga mat she’s used twice) and do lateral raises until your delts are screaming louder than a toddler denied a Capri Sun. Make your muscles burn so hard chlamydia seems like child’s play.

Do this for every major muscle group and you’ll look like Tyler Durden before next Tuesday.

Or so the story goes.

Unfortunately, if lifting a light weight for high reps was an effective way to increase muscle tone and definition, then every childcare worker on planet Earth would be walking around looking like a Calvin Klein ad.

These people are CONSTANTLY hoisting babies. (And, depending on the week, bottles of Cabernet.) Light weights, you know? And yet. Childcare workers do not, as a general rule, have biceps shaped like veiny little baguettes. Unless! Being toned and defined is like time travel, where going forward at Ludicrous Speed® sends you backwards, and the squishier and softer you get, the MORE jacked you secretly are? Are childcare workers just so absurdly toned that they’ve wrapped all the way back around to looking like a soft pretzel?

You’re more than welcome to explore this theory, but I’m putting my money on lifting a light weight for high reps being dumber than daytime television.

The best way to become more toned and defined is, weirdly enough, to stop training for tone and definition.

Slap somebody’s arm down on a table and — stay with me — saw their bicep clean in half. (Hypothetically. We are not doing this. Put the saw down.) What you’d find is a big ol’ bone, wrapped in a steak (that’s your muscle), wrapped in mashed potatoes (that’s your fat), wrapped in plastic wrap (that’s your skin). Your entire physical appearance is just a casserole of these four ingredients. Want to change how you look? Then you gotta change one of the ingredients.

Let’s rule out the obviously insane options first: bone and skin. Unless your five-year plan involves early-onset osteoporosis or skinning yourself alive like some kind of regional horror movie villain, those two are off the table. Which leaves us with the two dials you can actually turn: the steak (muscle) and the mashed potatoes (fat).

Here’s where things get trickier than rocking a rhyme: You can’t “tone” or “define” either of these attributes.

Muscles can either grow and get bigger, or they can shrink and get smaller. There is no special way of growing (or shrinking) a muscle that makes it “more toned” as opposed to “less toned.” (Not even sarcoplasmic hypertrophy. Story for another day.) In other words, you can’t tenderize your meat. There are bigger muscles. There are smaller muscles. There are no lean, toned, or defined muscles. Those words do nothing. They are decorative throw pillows.

Same deal with body fat — or, to use its fancier, more respectable government name: adipose. You can pile more of it on and get squishier, or you can melt it down and get harder. There is no premium, artisanal, small-batch adipose that makes you look MORE chiseled. All fat — visceral, subcutaneous, the weird brown kind scientists get excited about — sits on top of your steak amd obscures the view like fog.

Which begs the question:

If muscle mass and body fat can’t be toned or defined, how does one become toned and defined?

The secret is annoyingly simple. Appearing toned and defined is a byproduct of quantity, not quality. Golden Corral had it right all along. You need a mediocre amount of muscle mass, and a low amount of adipose. Miss the mark in either direction and your chances of looking toned and defined will sink faster than Squints in The Sandlot. (If that reference meant nothing to you, I regret to inform you that we cannot be friends. It’s not personal. It’s contractual.)

Look at impossibly skinny runway models. They don’t have much adipose, which is good for tone and definition. Adipose is mushy, like mashed potatoes. If you lather a steak with mashed potatoes, you won’t be able to see the steak’s striations. Unfortunately, super-skinny runway models don’t have much muscle mass; they don’t have steaks. They have a few tissue-thin slices of salami stuck to their skeleton. There are no striations to see, so they look like conscious coat hangers. They’d look more toned and defined if they gained muscle.

On the other end of the spectrum, there are heavyweight powerlifters and off-season bodybuilders. (The legendary Doug Hepburn comes to mind.) They have a bunch of muscle mass, which is good for tone and definition. Big steaks are dense and detailed.

Unfortunately, heavyweight powerlifters and off-season bodybuilders also have heaps of adipose; their muscles are covered in mountains of mashed potatoes. This suffocates the subtleties of the steak, smothering every striation. So instead of looking chiseled, they look like swollen sausages.

Between both extremes exists toned and defined bodies, like that of Brad Pitt in Fight Club and Brie Larson (who I only look at for research purposes). Their muscles are big enough to display detail, and their body fat levels are low enough to put the details on display.

Appearing toned and defined is a game of quantity more than quality: You need a big (enough) muscle and a low (enough) body fat percentage.

So if you aren’t as toned and defined as you like to be? You have two options. Lose fat. Or build muscle. Statistically, you probably need to do both. Skinny-fat guys (a group I have, let’s say, “personal field research” in) tend to overestimate how much muscle they have and underestimate how much fat they have.

Could I be wrong about your specific situation? Sure. You might already have sizable steaks, which means you should focus more on fat loss. Or you might already have minimal mashed taters, which means you should focus on more muscle growth.

I don’t know.

But I do know this:

There are dead wasps inside of figs. (Seriously, look it up.)

I also know this:

Training for tone and definition won’t help you lose fat or build muscle.

When knuckleheads train for tone and definition they usually lift a light weight for high reps, trying to make their working muscles burn. In order for this kind of training to have an impact on tone and definition, it’d either have to contribute to fat loss or contribute to muscle growth. Prepare yourself. It does neither.

I don’t care what the woman in the head-to-toe Lululemon told you between sips of her green juice: lifting something light will not trigger muscle growth no matter how many reps you grind out, for the same reason tickling your arm with a feather will never, ever produce a callus. The stress just isn’t big enough to make your body bother adapting. And the burn sensation that usually accompanies high-rep training? Doesn’t mean you’re burning fat.

I’m not sure who popularized the term “burning fat,” but whoever it was should have their private parts knuckle-punched. Fat doesn’t combust. It doesn’t smolder. It doesn’t even get warm. It gets quietly metabolized through chemical pathways with names like “beta-oxidation” that nobody’s ever going to put on a gym tank top, so undramatic, so utterly silent, that your body could be dissolving a love handle right now and you’d have zero physical sensation to show for it.

The burn sensation you feel mid-set is just lactic acid throwing a tantrum in your muscle. It’s loud. It’s dramatic. And it has nothing to do with the fat sitting six inches away, unbothered, watching the whole thing happen.

All of this means lifting light for high reps is, scientifically speaking, less effective than Goldeen in Super Smash Bros. (If you know, you know. If you don’t, bless you. Truly. Ignorance is a gift.)

Increasing the size of a muscle and decreasing the amount of fat surrounding the same muscle (to a significant degree) with one single exercise or training technique is impossible. Becoming (more) toned and defined has been and always will be a two-part process. You have to grow your muscles. You have to eliminate adipose. And if you aren’t doing either of these things, then you aren’t gonna be tightening or firming or toning or defining much of anything. Except, perhaps, a deep and abiding resentment toward your own body.