Is Fasted Cardio a Myth?

The bodybuilding world is always changing. New exercises, new methods, new diets and whatnot are always coming up. It can be difficult for serious bodybuilders to decide on particular techniques and diets etc.

Even seasoned bodybuilders can sometimes be confused. One such technique that is gaining a lot of traction is the fasted cardio. We have all heard of and love regular cardio.

But fasted cardio is a new way of doing cardio. The thing is, there are many questions around it. Such as does it work or is it a myth? In this piece let us look at it in detail.

So, is fasted cardio a myth? No, fasted cardio is not a myth. While a lot of the science is still on the edge- a lot of science still shows increased fat loss and less bloating when fasted cardio is performed. Plus, for some people it’s easier- I ALWAYS get side stitch if I run after I eat.

Plus, mathematically- it makes sense. Why would you eat 400 calories for ‘pre-workout energy’ just to run to burn 400 calories? It’d be the same as if you never ate or ran in the first place!

But, if you do fasted cardio, you’ll burn calories and eat after- making you fuller, burn more fat, AND be more productive in your goals.

What is Fasted Cardio?

Fasted cardio is exactly what it sounds like. It is cardio on a fast. The subject fasts for a prolonged period before carrying out the exercise session.

This is quite different from regular cardio where we usually take some sort of carbohydrates. Fasted cardio is not a new technique in the bodybuilding and fitness world- it’s actually really popular and has been for a long time!

Fasted cardio forces the body to burn body fat for energy instead of body glycogen. This means that fasted cardio immediately becomes a favorite of fat burners and people trying to shed body fat. The technique has been considered harsh by many since it is performed on an empty stomach.

Is Fasted Cardio a Myth?

How Does Fasted Cardio Work?

To understand how fasted cardio works, we will have to understand the way our body uses energy.

So basically what happens is, we eat food and it gets digested. After digestion, the food gets converted into glucose. This glucose basically gets dumped into the blood so that it can be transported throughout the body.

Now consider you go to the gym and lift a barbell. The cells in your muscles immediately make use of this glucose. They take the glucose and react it with oxygen to release energy which the muscles are capable of using to lift the barbell.

Now let us consider what happens during a fasted cardio. Fasted cardio begins with a prolonged fast. It is important to note that since we have just had a prolonged fast, our blood stream will have very little glucose in it.

Now let’s say you hit the gym. The question arises, how will the cell get energy to do any lifting? There isn’t any glucose available. Well, the body has another system in place. In case there is work is to be done and glucose is not available, the body is designed to use body fat for energy.

The fat on the thighs, face, and stomach, all are eligible candidates for this process. Once the body converts fat into energy to perform the exercise, the fat is gone from the body. Repeated practice of this will lead to fat shedding. The body picks up fat first from the more fatty areas such as the thighs or the stomach, face and arms come in later. This is how fasted cardio works. 

Is Fasted Cardio A Myth?

No, fasted cardio is not a myth. Fasted cardio works better than normal cardio when it comes to cutting down fat. This is because fasted cardio uses fat itself for energy.

So when the fat gets used up for energy, there is less fat left on the body.

What The Science Says

When it comes down to fasted cardio- the science heavily debates it.

The problem is, the science can only do so much. It’s hard to do a study like this, sometimes participants aren’t honest- and doing something like fasted cardio isnt’ easy.

The biggest obstacle however is determining fat loss. How many pictures and angles do you normally take every week to see if you’ve lost fat? I know myself I take a ton, and it’s often hard to tell.

Really, even in today’s day and age we don’t have the tools to just figure out someone’s body fat- which really makes studies like this hard.

However, the general consensus seems to be: Yes, fasted cardio does burn some more fat- but just a little bit, and we’re not entirely sure.

Like I said, it’s hard to do a study like this, but here are some references:

  • “We conclude that aerobic exercise performed in the fasted state induces higher fat oxidation than the fed state” (Viera AF 2016).
  • “~our findings indicate that losing fat seems to be the same regardless if you are using fasted cardio or not, but we need more long term studies to examine this” (Schoenfield 2014).

Is Fasted Cardio Good For You?

First off, fasted cardio isn’t for everyone. People who have issues such as diabetes, and other metabolism diseases should completely stay away from fasted cardio.

If such people perform fasted cardio they may experience different symptoms such as lightheadedness. It is best to contact your doctor prior to taking part in fasted cardio.

Everyone should be careful of the effects of working out on an empty stomach. To finish it off, fasted cardio is not for everybody. You should only engage in it if your body can take it.

Benefits of Fasted Cardio

Fasted cardio has multiple different benefits, let us take a look at some of them here:

  • Sheds more fat: Fasted cardio is famous for shedding fat. And it does it beautifully. Fasted cardio sheds more fat than regular cardio. This is the biggest benefit of fasted cardio. So, if your goal is to get rid of body fat, fasted cardio may be the best technique for you which you should start as soon as possible.
  • Saves time: Fasted cardio is done on an empty stomach. This means there is no tension of making and preparing a pre-workout meal. That is not even required. Therefore, fasted cardio saves everyone time. Of course you should be capable of exercising on an empty stomach, it is not easy for everyone.
  • Allows you to exercise before a meal: Many people prefer to exercise early in the morning, before a meal. This is a big advantage because fasted cardio allows you to do just that – exercise before a meal. Exercising before a meal gives you times for other things and planning other items of the day.


Fasted cardio is one of the most popular techniques these days that is gaining traction among the bodybuilding community.

The technique, as we learned, derives energy from body fat and thus helps get rid of body fat. However, for many exercising on an empty stomach may be problematic, especially for people with issues such as diabetes where low blood sugar levels can be fatal.

If you are moderately healthy, the fasted cardio technique is a good option for you to get rid of fat fast. When it comes to comparison between regular and fasted cardio, fasted performs better.         

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