As part of a UTMB® preparation diet, a frequently overlooked phase is training the digestive system, also known as gut training. Preparing your nutrition for ultra-trail is essential to avoid stomach problems during the race.
What is gut training?
Between 30 and 90% of ultra-trail runners experience digestive issues during a race (nausea, bloating, stomach cramps), often because their gut is not trained to absorb large amounts of carbohydrates during exercise. Gut training involves gradually conditioning the digestive system to receive, digest and absorb food and drinks during exercise, just as you train your muscles and cardiovascular system. Intestinal absorption capacity is not fixed: it improves with regular, progressive training.
The protocol to follow
The principle is simple: gradually increase the amount of carbohydrates consumed during long runs over several weeks. Start at around 30 to 40g of carbohydrates per hour on training runs of 2.5 hours or more, then gradually increase to 70 to 90g of carbohydrates per hour, consistently using the same products (gels, bars, drinks) you plan to use on race day. Allow around 4 weeks of regular training to see a noticeable improvement in digestive tolerance.
Recreating race conditions
Beyond carbohydrates, it is important to train your body to fuel with gels, energy bars and specialist drinks on all your training sessions, especially long ones, and to use the same nutrition you will find at the aid stations during the event. Following these basics will help you avoid digestive issues during your final high-intensity sessions, training weekends, or worse, on UTMB® race day.
FAQ
What is gut training?
It involves gradually training your digestive system to absorb large amounts of carbohydrates during exercise, reducing gastrointestinal issues on race day.
How long does effective gut training take?
Allow around 4 weeks of regular training, gradually increasing from 30–40g to 70–90g of carbohydrates per hour on your long runs.
