Running on an empty stomach: Is it good or bad?


Running on an empty stomach is undoubtedly one of the most discussed topics among the runner community. There are many athletes and people who decide to go for a run to lose weight or to eliminate that accumulated fat that costs us so much to lose. If we search the Internet in specific pages, blogs or forums, we will find many different answers about this topic. Many think that running fast is very dangerous, but there are also those who say that the advantages are apparent. In today’s post, we will try to clear some of your doubts and shed some light on this topic.

What do we mean by running on an empty stomach?

To understand this topic well, the first thing we have to do is to clarify what it means to run fast. If we are strict, to exercise on an empty stomach should spend at least 8 hours if ingesting food. For this, the easiest thing is to get up early in the morning to train, since we will have spent the whole night without eating. This means that early in the morning our reserves of carbohydrates are scarce, and therefore our body cannot use too many carbs to obtain energy while running, getting our fat reserves to burn. However, many experts think that this is not so simple.

Advantages and disadvantages of practicing fasting

Next, we will analyze what the advantages and disadvantages of exercising in fasting are.


  • According to some studies, going out to train to fast often along with a high-fat diet would help improve insulin sensitivity, and therefore the broker’s ability to store and optimize glucose reserve will be higher. Also, they assure that low sensitivity to insulin contributes to the fact that it is more expensive to lose body fat.
  • Another advantage that is given to exercise fasting is the increase in muscle glycogen reserve. This type of glycogen is only used locally; the muscle uses it to get energy during training.
  • Burn the reserve of body fat faster. Many experts speak of 21% more fat.


  • Running on an empty stomach is annoying and reduces athletic performance.
  • Training on an empty stomach consumes protein. Many believe that the athlete ends up obtaining energy from their proteins, which in the long run causes the muscle to weaken and eventually reduce.
  • A situation of hypoglycemia can occur, with the consequent dizziness or even fainting due to the lack of carbohydrates.
  • Dehydration may be suffered.


Adaptation. It is essential that the first time you are going to run on an empty stomach has not spent more than 7 hours without eating. It is best to start small, let two or three hours go by without eating. Starting suddenly is not advisable; the body is not used to it.

Hydrate. It does not have anything to do to leave to run in fasting with not hydrating. Drinking is necessary if we want not to suffer consequences such as dizziness, pájaras and others.

Provisions. Even if you leave on an empty stomach, it is advisable to bring a backpack with food and drink in case it gets complicated.

Recovery. Once finished the sports practice it is advisable to eat before an hour to achieve a functional recovery.


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