Debunking the Myth of Fasted Cardio


The word “cardio” comes from the Latin word “cervis”, which means chest. It was originally used to refer to strenuous physical activity such as running or walking around during the Roman Empire era. During the 19th century, it came into use as a term for any kind of exercise performed while standing up, but without moving your legs. For example, you could do sit-ups while sitting down.

In modern times, “cardio” refers to any type of vigorous physical activity done with no rest between sets or repetitions. However, some experts still believe that it is best to perform fasted cardio if you are trying to lose weight because it will result in less fat being burned off.

However, many other experts disagree with this idea. They say that it is not necessary to do fasted cardio if you want to lose weight. Some even claim that it might actually make losing weight harder since there will be less energy available after each workout session.


The main problem with fasted cardio revolves around the fact that you are burning primarily fat during a typical fasted cardio session. The body draws energy from three major sources: stored carbohydrates, stored fat and ingested food. It is normal for people to rely on ingested food for some of their energy needs. However, it is possible to train your body to access more fat than usual during exercise, even when you have not eaten anything.

In this scenario, it is true that more fat is burned than stored carbohydrates. The problem is that ingested food is never as efficient at burning fat as training without any food inside your stomach. As such, some people might actually lose muscle when they are constantly doing fasted cardio. This can result in a lower metabolism, which makes it harder to burn fat over the long term.


Fortunately, there is an easy solution to this problem. Instead of doing fasted cardio, you should eat some carbohydrates prior to the session. Studies show that eating a small amount of carbs about an hour before your fasted cardio routine will help you burn more fat than if you were to have ingested nothing at all. This is because the ingested food will increase your access to stored body fat while you are training.

You will also have more energy to burn during the routine.

Debunking the Myth of Fasted Cardio - gym fit workout

As such, it is best to eat a small amount of carbohydrates about an hour before your fasted cardio routine. You do not need to eat too much food, just enough to elevate your blood sugar levels. A small banana or several dates can work well for this purpose. You might want to stay away from foods that are high in fat since they can slow down the digestion process and keep your stomach full for several hours.


In many ways, fasted cardio is a waste of your time and effort. You could be eating carbohydrates before your workout so you can burn more fat during the session. You could also be eating plenty of high-protein foods and healthy fats to ensure that you are burning fat and retaining muscle. Many fitness professionals believe that it is better to focus on long-term results rather than short-term fixes.

The choice is ultimately up to you. If you want to try fasted cardio, there are ways to make the process safer and more effective. Just avoid the common mistake of doing too much too soon. Start with a shorter cardio routine and eat a small amount of carbohydrates before you begin.

You can increase the time or the intensity of your training routines as you get better at metabolizing fat. Just remember that you are the one who has to live with your body, so make the changes at a pace you know you can handle.

If this article has made you rethink your fasted cardio routine, you might want to take a look at our guide on how to break a plateau. We cover several different techniques for making consistent progress without destroying your body in the process.

Thanks for reading!

Sources & references used in this article:

Debunking the Myth of Fasted Cardio by S Khoury –

Debunking the Myth of Diabetes Mellitus as Cardiovascular Disease Equivalent: What Took So Long? by EI Bajwa, S Malik – Current Cardiovascular Risk Reports, 2018 – Springer

5 of Bodybuilding’s Biggest Myths Debunked by C Stan –

Debunking myths about the hospitalist movement by RM Wachter – The American journal of medicine, 2000 –

Conventional Risk Factors and Cardiac Events—Debunking an Old Myth About Prevalence by MF Read

Debunking some protein myths by PA McCullough, BA Franklin – Reviews in cardiovascular …, 1900 –

Debunking Internet Myths: What Is the Best Approach? by M Rajen –

5 Weight Loss Myths For Women by MAXM Plan – Reflections, 2012