How to Train Your Gut Before Race Day

You train for speed, endurance, and strength before toeing the starting line at a race, gradually building up your distance and pace to make sure you're ready to take on the miles.

- By Karla Walsh 

But sports dietitians confirm that most runners overlook one vital focus area during training-that is, your gut.

"Your digestive tract isn't used to running and taking in food at the same time. The constant up-and-down motion of running coupled with the blood flowing away from the gut and toward the working muscles usually results in a wonky stomach," says marathoner Natalie Rizzo, MS, RD, dietitian and founder of Greenletes in New York City. "But that doesn't need to be the case. Just like you need to train your muscles to run, you need to train your gut to accept the fuel it needs."

The more you practice, the better your gut will be able to handle the energy it needs, says Angie Asche, MS, RD, CSSD, a Lincoln, Nebraska-based dietitian and owner of Eleat Sports Nutrition. For any training run longer than an hour, consider giving your race-day nutrition strategy a trial run. That means eating the breakfast you would have on race day and consuming the fueling products you'll have midrun at structured intervals throughout your miles. Practicing your plan should then help you fine-tune your fueling come race day.

Because we all have different body sizes (and, as a result, energy needs) as well as gastrointestinal (GI) tracts, the best fueling strategy looks different for each person. However, a study published in 2021 in Nutrients and a review published in 2017 in Current Opinion in Gastroenterology recommend that if you notice an upset stomach or diarrhea while running, steer clear of the following items for the two hours prior to and during a run: