Cardio On An Empty Stomach For Faster Fat Loss – Myth Or Truth?

By nutritionist
Last update: 05.03.2018

Simply complete the cardio on an empty stomach and thereby reduce more body fat while losing weight? This is exactly what many self-proclaimed “fitness gurus” claim.

But is that even true? Are you sure you lose more fat by doing cardio before breakfast?

In this post, we’re going to look to see if there is anything to this claim or if it’s just a myth.

If you exercise sober, you burn more body fat?

We are known to be in a sober state immediately after getting up. Depending on how long we slept and when the last meal was eaten, we have been fasting for about 8 to 10 hours.

As a result, our insulin level is very low, since the hormone has not been released for a long time, as would be the case, for example, after eating carbohydrates or protein. In addition to this, the amount of carbohydrate stored in the body, also known as glycogen, is also lower in the morning.

Because our bodies burn more fat when insulin levels are low and glycogen stores are not full, it has long been suggested that cardio on an empty stomach would lead to improved fat loss.

The problem with the whole thing, however, is that a mistake was made in making this thesis.

The mistake of reasoning

While it’s true that more body fat is used as a source of energy during an empty cardio exercise, overall that doesn’t automatically mean that you would lose more fat throughout the day.

This fact has already been proven in scientific studies, some of which we will now look at.

Study 1

In this scientific investigation 20 women were divided into two groups.

One group did the cardio training on an empty stomach, while the other group was allowed to eat a meal before the training session.

The training sessions lasted 1 hour in total and 3 units per week were carried out.

And the result?

While both groups ended up with less body fat, the empty cardio did not lead to increased fat loss and was therefore useless in this regard.

Study 2

At this study it is a so-called meta-analysis. Here, the results of numerous other studies are combined into one large final result, which makes the whole thing more meaningful.

A total of 5 studies met the criteria that were necessary for the study to be considered.

In the end, the scientists came to the conclusion that cardio on an empty stomach did not lead to increased fat loss or an overall increased weight loss.

Study 3

Another study confirmed the basic thesis that more fat is used as an energy substrate during endurance training on an empty stomach.

At the same time, however, the scientists also found that with such a procedure, less fat is burned in the hours after the workout.

The group that had eaten before the cardio consumed more body fat as a source of energy afterwards. The group that did the cardio on an empty stomach burned more carbohydrates in the hours after the workout.

For this reason, the researchers even concluded that a light meal before training would be recommended.

Why cardio on an empty stomach can still make sense to you

As we have just seen from the 7 studies in total, doing cardio on an empty stomach is not beneficial in terms of fat loss.

Despite everything, such an approach may make sense to you. But why?

Quite simply: If it is easy for you to implement in practice or if you feel better sober during the unit, then that’s the way it is.

The only thing you shouldn’t believe is the myth that an empty cardio leads to more fat loss. Many people who fell for this statement forced themselves to do the endurance training before breakfast.

And that’s only because they believed any people who brought this myth into the world.

Just like with nutrition, in the end you should do what makes sense, can be sustained for a long time and thus ultimately gives you the best results.

Sober strength training for better results?

Since strength training protects the muscles from degradation and can even build muscles when losing weight, it is clearly the more recommendable sport.

However, amino acids are required to build muscle mass. For this reason, training on a completely empty stomach is not recommended.

It is true that this will not result in huge disadvantages, but in spite of everything, such a procedure may be associated with disadvantages.

For this reason, you should at least consume some protein before strength training.

That can either be in the form of Whey protein * happen or through another source of protein such as cottage cheese or curd. Otherwise, nothing speaks against strength training on a relatively empty stomach.

Why BCAA don’t make sense, not even before training on an empty stomach

As you may know, I am not a fan of the additional intake of so-called BCAA (branched chain amino acids).

This is because these are only 3 different amino acids and not a complete, high-quality protein.

This is exactly why BCAA work, for example, much worse than whey protein. Since they are also significantly more expensive per kilogram, they are a product that is nothing but a waste of money.

They are therefore not recommended before strength training or cardio on an empty stomach.

What should you eat after your workout if you are exercising on an empty stomach?

Even after cardio or strength training, protein should be consumed within 30 to 90 minutes.

In addition, carbohydrates are also recommended, as the carbohydrate stores are emptied during training in the higher intensity range.

Some fat can of course also be incorporated into the meal after the workout.

Overall, a good mix of the 3 macronutrients is appropriate. In the case of protein, care should also be taken to ensure that approx. 30 grams are consumed from a high-quality source.


In terms of fat loss, cardio has no benefits on an empty stomach. Because the calorie deficit is still decisive for this.

If you still want to do the endurance training before the first meal, you can of course do so. In strength training, on the other hand, it is advisable to take in at least some protein beforehand, in order to remove potential disadvantages.

Have you ever done sober cardio, or at least heard of the myth that it helps you lose more body fat?

Feel free to leave a comment now, even if there are any questions.

Until then, I’ll say goodbye for the time being. Greetings and see you soon, Lukas.