Up until a few years ago, it was considered normal for sportspeople to have digestive problems while exercising. Now we know that digestion is difficult when exerting oneself physically. The reason for this is because the heart is sending most of the body’s five litres of blood to the muscles, skin, lungs, and to the heart itself. 

“One of the organs most disadvantaged during this process is the digestive system: the fact that blood is removed from the digestive system while we exercise makes it difficult to eat and drink while doing so. Furthermore, when exercise is very intensive or prolonged, the walls of the digestive system undergo changes. This concept is called leaky gut syndrome or intestinal permeability: not only is the digestive system not receiving blood, but if we don’t take special care, in many cases damage can occur”, explains Dr. Toña Lizárraga, a specialist in sports medicine and nutrition.

How can you take care of your digestive system?

Athletes should eat foods that are easy to digest and do not ferment too much, or that pass quickly through the digestive system. For this reason, many sportspeople avoid foods that contain fat, fibre and even milk, often eliminating gluten as well. Another way to take care of your digestive system is to regularly take probiotics and other nutritional supplements that focus on intestinal health.

“We now know that there are certain foods with carbohydrates that, although they seem appealing for sports practice, they have elements which ferment. These elements are found in certain fruits and vegetables such as cabbage or artichokes, as well as legumes or foods that contain a lot of fibre, which can remain in the digestive system for a longer period of time and ferment. This also causes atheletes to experience gas, a slow and heavy digestion, and discomfort,” added Dr. Lizárraga, who leads FC Barcelona’s nutrition department.  

As a result, for match day it is recommended to avoid certain fruits with high levels of fructose or fermentable carbohydrates. During this time foods that are high in fibre should be avoided, even if the foods are highly healthful and recommended in their day-to-day diet. For this reason, if someone is going to practice sport, it is recommended to eat foods that are easy to digest such as white rice, carrots or pumpkin.

This is called a low FODMAP diet, which stands for the related types of carbohydrates and alcohols: fructo-oligosaccharides, disaccharides, monosaccharides and fermentable polyols.

The importance of professional advice

It is crucial for sportspeople to receive professional advice from a doctor who specialises in nutrition, or from a dietitian or nutritionist. In this regard, Dr. Lizárraga reminds us that their guiding role is essential. “A sportsperson can get confused as they might be eating foods that are healthy and recommended, but their digestive system is very delicate and they can experience a lot of discomfort while exercising”.

For this reason, Dr. Lizárraga believes that it is very important that the concept of functionality be explained to the sportperson by a professional. It is possible that they use a gel, a sports drink or a certain food because another athlete recommended it, or because they love the flavour and think it will be great for match day or for the race they are about to run. However, while they are practicing sport, they could suffer diarrhoea or end up needing to go to the lavatory.

Training the gut

“It’s not the food, the gel or the drink that causes this situation. It’s the constraints from exercising which prevents the food from settling as it would do if you weren’t moving. Additionally, it’s important to keep in mind that if you’re involved in sports, you will require more of these types of foods. And if your gut is not well-trained, you will experience discomfort. We are learning more and more about how the gut can be trained, just like muscles can be trained: eating and drinking while exerting effort requires training and knowing what settles well with your body and what doesn’t. It’s good to practice with a few foods and incorporate them little by little so that the gut is able to adapt to them,” Dr. Lizárraga concludes.

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The Barça Innovation Hub team