Fasted Cardio – Good or Bad? Featured Image

Fasted Cardio, good or bad?

Ok so here’s to trying to explain fasted cardio to a skeptic.

For years people have done cardiovascular activity first thing in the morning on an empty stomach in hopes of reducing bodyfat faster. Here’s why. Yes, when you wake up and begin low intensity cardio on an empty stomach with no carbohydrates for your body to convert to glycogen and use as energy then your body begins to use fat in the form of fatty acids as an energy source.

True you will burn slightly more bodyfat during this single cardio session than if you had a full breakfast. However you will also begin to tap into some lean tissue as well utilizing muscle as a source of energy too. The only problem with this “fat burning fasted cardio state” is that this only occurs with extremely low levels of activity (walking, etc) and that the rate of breakdown is still usually higher than your muscles can uptake them for energy so your left with extra fatty acids in your bloodstream that are then put right back to where they were to begin with. So not only are you left feeling like crap, hungry, tired, and doing zombie like cardio, but your still in the relatively same place you were when you started. Good or bad, you decide.

But, what you could do. Is wake up and feed your body quality fuel like eggs and oats since you’ve been fasting while you sleep anyways. give your body some carbohydrates and protein to fuel a moderate to intense training session, feel better doing it, and burn more calories during and after the workout because you trained harder and thus have a higher EPOC (post burn). Thus, in a given 24 hour period burning a total of more calories equaling more and faster fat reduction.


This is just a simple breakdown of how to look at this “theory.” There are still numerous more factors that go into account of fat reduction relative to fasted cardio. However that’s an entirely different post. You can get super technical with type of foods consumed and the thermogenic effect from the food, digesting rates/timing, type and intensity of training done, methods used to quantify the actual intensity such as MET’s, oxygen consumption, oxygen uptake, HR, HR reserve, which will decline with age, current age, weight, sex, body fat, ergogenic aids, and so many other factors that only clinical lab settings can determine down to the hour what your body will do.

Your body goes through several processes and energy pathways during the day and at various activity levels so it is very difficult to say that the benefits from fasted cardio outweigh the benefits of a feed and fueled human body. The human body does not have switches that turn on and off for fat burning. On top of that every human body is completely different and for the sake of keeping this article simple we will close with the idea that fasted cardio is relatively “pseudoscience” aka “bro-science”


So I know what I will be doing and what we recommend to our clients but you decide.

PS: Check out these great at home cardio workouts: Simple 30 Minute Cardio Workouts!

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