Train your gut: build up to 90 grams of carbs per hour
Your gut adapts to what you feed it, the same way muscles adapt to training. With a few weeks of practice you can take in more fuel with fewer stomach problems.
Why train your gut
Regular practice with food and fluid during sessions does four things.
- The stomach empties faster, so it feels less heavy and sloshy.
- The gut wall builds more of the transporters that take up glucose and fructose, so it can absorb more.
- Athletes report less nausea, gas, cramps and urgent toilet stops in races.
- Blood sugar stays steadier, because fuel arrives more evenly.
A build up plan
Expect at least 6 to 10 weeks, folded into your preparation for a main goal. In long sessions of more than 90 minutes:
- Weeks 1 and 2: 30 to 40 g of carbohydrate per hour.
- Weeks 3 and 4: 60 g per hour, for example one gel plus 500 ml of isotonic drink.
- Weeks 5 and 6: 75 to 90 g per hour, with a glucose to fructose ratio of 2 to 1.
- Weeks 7 and 8: test your race plan, for example 90 to 120 g per hour at a ratio of 1 to 0.8, in at least two or three hard sessions or a dress rehearsal.
Two more ways to practice
Volume: in long sessions, drink bigger gulps and work up to 0.8 to 1.0 liters per hour instead of small sips, so the stomach learns to pass large volumes.
After a meal: now and then do an easy 30 to 60 minute session shortly after a normal carbohydrate rich meal, so you get used to training while digesting.
Things to keep in mind
- Do it once or twice a week. The adaptation fades quickly when you stop.
- Test at or near race intensity. At a high heart rate the gut gets less blood, so digestion is harder than in an easy session.
- Nothing new on race day. Use the products you trained with.
How much is too much?
The research points to 90 to 120 g per hour as the upper range. Pro cyclists and triathletes sometimes reach 160 g per hour, but that is not realistic for most amateurs. Find your own ceiling, build up slowly, and bring in a sports dietitian when you aim for the top end.
When it keeps going wrong
Complaints high in the stomach, such as nausea and reflux, usually come from the stomach. Cramps, diarrhea, gas and bloating usually come from the intestines. Fat, fiber and protein are the most common triggers, and solid food causes more trouble than liquid. Check your fiber in the days before and the glucose to fructose ratio of your products. If symptoms persist or you cannot explain them, talk to a doctor or a sports dietitian instead of fixing it alone.
General information for healthy adults, not medical advice. If you have diabetes, a gut condition, an eating disorder, or take medication, talk to your doctor or a sports dietitian first.
Common questions
How long does gut training take?
At least 6 to 10 weeks, built up step by step. You keep the benefit by practicing once or twice a week.
Is 120 g of carbs per hour realistic?
For most people, no. It is the top of the research range, and only for athletes who built up solidly and tolerate it well in training.
What should I do if I get stomach cramps?
Check the products first: fat, fiber and protein, polyols, and the ratio of glucose and fructose. Stay with liquid carbohydrate and build up more slowly. If it persists, see a doctor or sports dietitian.
Want this planned around your own week?
The 2fuel app turns every training session into kcal, carbs per hour and protein, then into meals. With an AI coach or a sports dietitian. In beta now.