Research · Nutrition ·
Can you train your gut for race-day fuelling?
Gut problems are one of the most common reasons for a bad day in an ultra. This study tested whether the gut can be trained to handle carbohydrate during running.
What they did
Runners did a 2-hour run at a moderate intensity (60% of VO2max), taking 30g of carbohydrate every 20 minutes, followed by a 1-hour distance test. This was the "gut challenge".
They were then split into three groups for two weeks of repeated gut-challenge training:
- Carbohydrate gel-discs
- Carbohydrate food
- Placebo (no carbohydrate)
After the two weeks, everyone repeated the original gut challenge.
What they found
- Gut symptoms dropped by 60% in the gel group and 63% in the food group, more than in the placebo group.
- Both carbohydrate groups improved their running performance compared with placebo. Monash University's summary of the study put the gain at around 5%.
- The gel group also absorbed carbohydrate better and had more glucose available in the blood during running.
What it means for ultra runners
Your gut adapts to what you practise. If you plan to take carbohydrate on race day, start doing it regularly in training, not just in the final long run. Practise with the products or foods you'll actually use.
Limitations
- The runs were 2 hours at moderate effort, much shorter than most ultras.
- The intervention was only two weeks.
- It was done in a lab, not on trails or at race intensity.
This is a summary for information only, not medical or dietary advice. Read the original study for full details.