What do you think are the most important aspects that make a great athlete? I bet many of you would say powerful muscles, lean physique, a big heart, efficient lungs and a calm & strong mind. I´m sure not many people would think of the gastrointestinal tract (the gut) to be a key organ in getting the most out of your performance. Funnily enough - it is and it can take you from hero to zero in minutes during an important competition.
If you are a cyclist, runner, triathlete or ultraendurance athlete, this blog post is highly recommened!

What is training the gut?
Training the gut is a method used in the sports nutrition world to help athletes handle and absorb higher amounts of carbohydrates from multiple sugar types (both glucose & fructose). This helps reduce stomach distress by limiting gastric issues associated with exercise such as cramping, vomiting, nausea, diarrhea, bloating, the ´fullness´ feeling and side stitches.
Training the gut is a key fuelling strategy that allows the body to absorb more carbohydrates by increasing oxidation and creating a faster delivery of energy to the muscles. It is a special technique all endurance athletes should practice.
Why is it necessary?
Particularly during high intensity and/ or prolonged endurance events, maximising carbohydrate availability per hour plays a critical role in ensuring optimal performance and can help you go harder for longer. An example of what may cause gut distress when consuming large amounts of carbohydrates are concentrated sports drinks. The ingestion of a beverage loaded with carbohydrates causes a shift of fluid from the blood into the lumen (located in the large and small intestine), which will lower osmolality there. This shift causes senstations characterised as cramping.
The pros are not immune to gut distress, many top elite athletes have lost races or failed to finish due to intestinal cramping, particularly those involved in marathon type events. Pros such as running olympians, Mo Farah and Usain Bolt or Tour de France riders, have all had to deal with this some time or another in their careers. Although gut issues during exercise are most common among endurance athletes due to the larger amounts of carbohydrates needed during prolonged exercise, it can happen to anyone.
How do I train my gut?
Train with a large amount of fluid in the stomach (1)
Train immediately after a meal high in carbohydrates (1)
Consume high carbohydrate intakes during training (1)
What type of food should I train my gut on?
Foods from multiple sugar types such as gels, sports drinks, bananas, rice cakes, dates or date balls are all good examples of foods you can use to test your gut´s threshold. Large amounts of carbohydrates per hour range from 60-90g and for some extreme cases up to 120g. Remember, such large amounts are only necessary and beneficial for exercise durations of >3 hours and depends on the intensity at which you are aiming to achieve. For athletes exercising for 1-2 hours, 30-45g per hour is sufficient to avoid fatigue and overloading the gut.
Do you want personalised nutrition advice?
References
1) Jeukendrup, A.E., (2017). Training the Gut for Athletes. Sports Med. 47, 101–110.