Your friend, family member, coworker, stranger you follow on social media who you place more trust in than you fucking should, is probably doing fasted cardio and telling you about all the great results they’re getting.
So you’re probably thinking about doing fasted cardio because, fuck, if a shitload of people are doing something then it must be something you have to do too.
Because it has to be a good thing or else so many people wouldn’t be doing it…like investing money with Bernie Madoff.
Talk about a sure thing!
Yup, it has to be good if everybody and their mom is doing it!
Is fasted cardio among the many, many things the masses have been right about?
I. What’s In A Name?
If you couldn’t tell by its name, fasted cardio is cardio performed on an empty stomach, preferably upon waking in the morning.
Yes, that’s right.
Fasted cardio calls for making your cardio session even more horrible than it already is, which is by the simple virtue of it being cardio.
The thinking is that without enough glucose to use for energy because you’ve went for a couple of hours without food, your body has no other choice but to burn fat for fuel. This is opposed to eating and signaling the release of insulin, a hormone that not only transports glucose for immediate energy or stores it as fat for later use but also suppresses lipolysis, or the breakdown of fat.
Makes sense not to eat, right?
Well, it turns out that fasted cardio does exactly what it’s advertised as doing.
Yup, it burns fat…
…to a certain extent.
II. Happily Never After
About 20 percent more fat is burned during a fasted cardio bout than one performed after eating.
That’s good news!
Or is it?!
While fasted cardio burns more fat, it’s not exactly the kind of fat that matters.
The type of fat that all forms of exercise burn are intramuscular triglycerides (i.e. stored fat in the muscles), which have no impact on health or appearance. It’s this type of fat that fasted cardio burns with greater efficacy.
It’s the visceral and subcutaneous fat that we care about (i.e. the fat making up your love handles and many, many, many other trouble spots). Those fat stores are tapped into by elevating the metabolic rate, or increasing the body’s energy expenditure. Fasted cardio fails to do this, as the calorie-burning effect takes place only DURING the bout but not AFTER.
III. Debt Collection
Wanna know what helps burns fat when you’re not doing shit?
It’s good to see that you’ve been paying attention and know about the benefits of weightlifting, but that’s not what I was going for.
The answer is high-intensity interval training (HIIT) and food.
Eating prior to a cardio session burns more fat in the 24-hour period following the workout because exercise increases the thermic effect of food (TEF), with the body using even more energy than normal to break down the food, a process which carries on for the rest of the day.
As for HIIT, the all-out bursts of activity produce lactic acid, which places a demand on the body for oxygen to eliminate the toxic substance that fatigues muscles. Then because so much oxygen is used during the workout in order to oxidize lactic acid to carbon dioxide and water, the body has to take in excess oxygen after the workout to return the body to its normal resting state. This excess post-exercise oxygen consumption (EPOC), as well as other recovery processes, requires energy and turns the body into a calorie-burning machine for hours on end.
So perform HITT fasted, you say!
Not so fast (see what I did there?)!!!
While eating breakfast isn’t necessary for each and every person, a hypoglycemic state for most of the population will preclude them from performing at a high enough intensity to reap the afterburn effects of EPOC. They just won’t have the energy to.
IV. Because I Got High
For most people, cardio on an empty stomach will impair their ability to go hard, limiting the number of calories burned during the session and throughout the day as part of the post-exercise afterburn effect.
Additionally, because fat isn’t the only power source that your body turns to when glucose is scarce, the caloric cost of exercising without a meal is double the amount of muscle tissue, or protein, burned when in a fed state.
Performing fasted cardio at a high intensity only worsens this.
As I’m sure you know, cortisol is a stress hormone that triggers the release of amino acids, glucose, and fatty acids for energy. That’s one of its many functions. Its levels are at the highest in the morning because of the overnight hours spent without food, in addition to the role it plays in helping you wake up. As such, your body is in a catabolic state, primed to break down molecules for energy. Since glycogen isn’t available because you haven’t eaten in hours and the body would rather preserve its fat deposits for future emergencies, the prime candidate is muscle tissue for amino acids. Eating will prevent this catastrophe and lower cortisol levels. Not eating and then going balls-to-the-wall on the treadmill will only jack cortisol levels sky high.
What that means for you is that if you’re unable to bring your cortisol levels down (which you may not if you’re pairing your cardio with a caloric deficit like someone with a brain would if they were after fat loss), your body will spend most of the day in catabolism.
Yes, your body will spend most of the day eating away at that hard-earned muscle that you kinda sorta need to burn shitloads of calories at rest!
V. What’s In A Name…Again?!
Now, I know what you’re thinking.
Like, how could I not?!?!
After all, I’m omniscient.
What you’re obviously thinking is that if fasted cardio has the potential to burn all-important muscle, then why do bodybuilders, bikini girls, and other physique competitors do it religiously?
Because they’re on anabolic-androgenic drugs.
And what do anabolic-androgenic drugs do?
Anabolic-androgenic drugs place you in a constant state of…ummmmmm…anabolism, or muscle building, effectively blunting the effects of elevated cortisol and allowing users to preserve muscle as they tap into their fat stores.
People not on anabolic-androgenic drugs will lose WEIGHT by doing fasted cardio, but it’ll primarily be water and muscle — not FAT — as demonstrated.
VI. Special Treatment
When people get on a fitness kick, they often start out aggressively, doing things that impair fat loss.
You know, things like dropping their calories from maintenance to starvation, eliminating whole food groups like dietary fat and carbs, working out for hours and hours on end, popping every fat burning pill known to man.
Fasted cardio is another thing we can add to the list of shit that people do with the best of intentions.
Bless their heart!
As we see, while almost everyone is doing fasted cardio, it’s truly a protocol for more, let’s say, “special” trainees.
If you’re not “special”, stay the fuck away from fasted cardio.
Don’t believe me, though?
Still think fasted cardio is the Holy Grail?
Then at least drink coffee or green tea (both without milk or sugar) for the energy needed to go at a high intensity and take a branched-chain amino acids (BCAAs) supplement to try and minimize amino acid oxidation (i.e. protein breakdown).
Do at least those two things so you don’t come off being that “special”, and that’s in the other sense of the word!