To eat or to not eat feels like one of the biggest decisions to make before working out… especially before doing cardio. And, while I’ve always been one to never give myself enough time to eat in the morning before a run (or before literally anything), I’ve been starting to fast intentionally to see what all the hype about fasted cardio was on my TikTok FYP — and honestly, it’s worth the sweat.
A hot topic in the fitness world, fasted cardio involves exercise that gets your heart rate pumping without a snack or meal beforehand, generally first thing in the morning about 10-12 hours after you last ate. This way, your body dips into its stored fats instead of glycogen for energy, promoting the health benefits that everyone is raving about today.
But, like every sporadic fitness trend, fasted cardio has its fans and haters, and the best way for you to know if it works for you is to simply give it a shot. So, if you’re typically one to snack on a banana, chug an energy drink, or even down a spoonful of protein powder before your cardio workout… put it to the side, bestie — try fasted cardio and save your snack for after (because everything tastes better as a reward anyways.)
What is fasted cardio?
The first thing I’ll highlight is that fasted cardio is not for everyone. While some can easily skip a bite to eat before their workout, others rely on it to get through, and that’s OK. Everyone is different. And, after all, you’re moving your body at the of the day, so what does it really matter?
But, for those of you who can handle this kind of exercise (and have maybe been doing it accidentally all this time anyway, like me), it has its benefits. Multiple studies have shown that fasted cardio can improve endurance through an increase of VO2 max (maximal oxygen consumption), can increase the human growth hormone (HCH) which regulates metabolism and growth, and can stimulate digestion by helping your body move gas through the digestive system to, overall, reduce bloating.
what are the risks of fasted cardio?
Fasted cardio is not just a hot topic in the fitness world out of pure pros — it has its cons list, too. Depending on what your fitness goals are, fasting might be something you can avoid or replace with something that can, in its place, garner the same effects. Nonetheless, there are some things you might want to know before even simply trying fasted cardio.
The first is that you can run the risk of low blood sugar when fasting in general, which can lead to dizziness, fatigue, and over exhaustion during your workout. If you’re someone that’s prone to low blood sugar, consult your healthcare provider or professional before giving it a try.
Other risks include dehydration, reduced strength and muscle function, compromised cognitive function and balance, and increased cortisol levels. If these are things you’re worried about, you can always start incorporating the exercise bits at a time, or contacting a professional for advice.
My experience with fasted cardio:
In the past, I’d never made any correlations between running on an empty stomach and how I felt, physically and mentally, during the run and after. Though I’d grown up being told to at least have a quick bite before my run, I never noticed any groundbreaking sickness during or after a workout when I skipped a snack — only maybe a slight increase in exhaustion, hunger, and irritation.
This is to say, I find that fasting intentionally before a workout versus accidentally skipping out on a bite to eat makes me feel a lot better, both during and after a workout. Working out on an empty stomach today (except for the off day here and there) allows me to feel an increase in my mood, endurance, and overall health.
There are so many elements that go into fasted cardio that you might find it doesn’t work for you. Just because I’ve had a good experience so far doesn’t mean that you will, and that’s OK. This doesn’t have to stop you from trying, and it doesn’t have to stop you from personalizing this style of training, either. Maybe you find that it’s better capped at 30 minutes versus one hour of fasted cardio, or maybe you’d rather have a brisk walk than a run — I mean, I found my groove, what’s stopping you from finding yours?
A few Things to remember before trying fasted cardio:
Nothing has saved me during fasted cardio as much as my water. That to say, there are things you’ll want to remember while doing fasted cardio to ensure you’re doing it safely and in a healthy manner.
As important as water is, saving your fasted cardio for lighter workouts — such as jogs, brisk walking, yoga, and low-intensity Pilates — will be your best friend. I would not suggest running a half marathon on an empty stomach unless you want to end up at the ER.
To prepare, having a before-bed snack is a good idea. While you want to wait at least 10 hours before your cardio workout, you want to make sure your last bite was a well-balanced one, preferably high in protein. My go-to is a yogurt and granola bowl, but this can be anything you think would work best for you.
And, of course, what’s a fasted cardio workout without the yummiest meal as a reward? You want to make sure that you refuel yourself properly afterwards with a well-balanced, protein-heavy, hearty meal. For this, my go-to is usually toast, scrambled eggs, turkey bacon, avocado, and fruit (chef’s kiss). I promise, it’s the best feeling of accomplishment afterward.
Is fasted cardio worth the hype?
After years of accidental fasted cardio workouts, I can safely say that when you do it in a way that is intentionally healthy and that works best for you and your individual needs and goals, it is, in fact, totally 100% worth the hype.
While it can increase weight loss, reduce bloating, and burn stored fat, it can also improve your mood, stress, and anxiety levels. It is just as much a mental workout as it is a physical workout — and that’s why I love it.