cardio
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 something classical. A Greek statue. 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.
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. This statement alone is enough 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 why we need to unpack the beginnings of this booby trap.
Why does everyone think cardio is required to get six-pack pixelated?
Cardio is often recommended because, a long time ago, some lab-coated sleuths discovered that triglycerides are the primary fuel source for aerobic respiration. 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 those systems is the aerobic system, and it tends—tends—to favor triglycerides. 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 be forced to chew through some of the triglycerides stored inside 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, aerobic-system-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? Good. You should be. But this is a story for another day.)
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 appears when income quietly outpaces 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.
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 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.”
No.
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.