Many magazines advocate fasting sports and most people who practice it do so with the aim of losing weight, and especially fat mass. But is it so beneficial for our body? And what are the dangers of such a practice?

The benefits of fasting sports

Exercise on an empty stomach for better performance

The first benefit to pin is digestive comfort. We all know that when we exercise on a full stomach, we feel bloated, lacking in energy and our performance suffers. However, to avoid any digestive discomfort, simply eat lighter or have a snack such as fruit, nuts or a cereal bar before your workout. Some sports, such as yoga, are best practiced on an empty stomach because of the many positions in which the body contorts. 

Exercise on an empty stomach to burn fat

Another advantage, and not the least, is that fasting sports allows the body to train to use another energy channel which is the fat burning.

Here's a quick explanation: in normal circumstances, our body uses carbohydrates as its main fuel. These carbohydrates are present in our blood and, in reserve form, in our liver (liver glycogen) and in our muscles (muscle glycogen). During an effort, our muscles consume the carbohydrates present in our blood in priority and when these are exhausted, they attack the muscle glycogen, the liver glycogen being mobilized for the other organs requiring the consumption of carbohydrates (like the brain). The carbohydrates not converted into energy, will then be stored by our body as fat. 

When we play sports, liver and muscle glycogen reserves are at their lowest and there is little or no sugar in the blood. The body is then obliged to turn to another source of energy present in the body: fatty acids. The body then starts to burn fat.

By training the body to use this metabolic pathway, we prepare it for endurance efforts of long duration such as cycling, marathons, triathlons, ... Indeed, in these sports, the body consumes a lot of carbohydrates and when the carbohydrate reserve decreases, the athlete often finds himself or herself with a drop in energy and therefore in performance. But once trained, it is ready to mobilize fat when carbohydrate resources are exhausted. 

Losing weight by exercising on an empty stomach

And finally , the benefit that most people are looking for weight loss. By training your body to draw on fat, it will more easily trigger the melting of body fat. Be careful, however, to eat properly after the effort to allow your body to recover. Otherwise, it will tend to do the opposite of what you want, which is to store fat. 

The risks of fasting sports

Despite all of the benefits mentioned above, it's important for you to know thatexercising on an empty stomach is not without risk to your health. 

First of all, it is not recommended for people with fragile health, people suffering from diabetes and in people who do not practice sports regularly or after a long break. In any case, caution is required and it is advisable to consult a doctor before starting.

One of the risks involved, is to drop your blood sugar levels too low. If the carbohydrate stores in the blood, muscles and liver are depleted, this can lead to : 

- dhypoglycemia. These can range from a simple craving to dizziness and difficulty concentrating. Remember that your brain works primarily on sugar and water. This risk is important if your body is not used to long term efforts.

- muscle wasting. The lack of glucose causes your body to try to produce it on its own. To do this, it will use the amino acids at its disposal. Since these amino acids are the basic building blocks of protein, your muscle mass will melt away.

- fatigue. It even goes to the point of exhaustion. This fatigue can lead to decreased performance, headaches, depression, constipation or diarrhea and other miscellaneous ailments.

Another risk incurred by this type of practice is the making of ketone bodies due to the breakdown of fatty acids. If these ketones are present in the body in excessive quantities, they accumulate in the blood and become toxic. This can cause kidney problems and poor recovery after exercise.

Also watch out for fat storage. By dint of depriving your body, it tends to store more. In addition, you may feel hungry for the rest of the day, which often leads to snacking and the associated weight gain.

Sport on an empty stomach: our tips

Here are a few tips to take full advantage of the benefits of sports on an empty stomach.

• Anticipate by consuming carbs the night before. This allows glycogen to be stored in the muscles so that reserves are not at zero when you wake up. 

• Hydrate well and if necessary, eat a low-carb breakfast. You won't be fasting completely but you won't lose the benefits and take an energy bar, compote or fruit with you in case of low blood sugar. 

• Don't do a session that is too long or too intense. Choose low-intensity endurance sports. And above all, avoid starting the sport in the morning. Wait at least 30 minutes before starting. 

• After sports, eat breakfast to optimize recovery and avoid fat storage.  

As you can see, there are many benefits to working out on an empty stomach but there are also many risks. Don't jump in without thinking it through and considering all the drawbacks it can cause.