How to Avoid Runner's Trots

Q. Should I go on a gluten-free diet?

Gluten, a protein found in wheat, is known to cause diarrhea in people with celiac disease. About one in 125 people has celiac (gluten intolerance). First, get a medical diagnosis before embarking on this difficult diet. Even if diagnostic tests are negative, some people feel better avoiding gluten. For more information, see and

Q. I'm afraid to eat or drink anything during exercise. If I succumb, I inevitably get diarrhea. Suggestions?

I suggest you start drinking earlier and stay well-hydrated. Intestinal complaints are common in athletes who have lost more than 4 percent of their body weight in sweat. That's six pounds for a 150-pound athlete. Becoming dehydrated may have triggered the diarrhea, not the water or sports drink.

Your best bet is to train your body to tolerate fluids. Start with small amounts of water during exercise for a week or two, then transition to diluted sports drinks, and then eventually to full-strength sports drinks. Or have plain water and mints or hard candies.

Q. Can I take some sort of anti-diarrhea medication?

When all else fails, consult with your doctor about taking anti-diarrhea medicine, such as Imodium, one hour pre-event. Perhaps that will be your saving grace for special events, but not on a daily basis. Caution: Taking Imodium without diarrhea can leave you constipated.

Q. Any other tips to help manage dreaded diarrhea?

  • If you are a morning runner, drink a warm beverage (tea, coffee, hot water) to stimulate a bowel movement. Allow time to sit on the toilet to do your business prior to exercise.
  • Before you embark on a hard workout, exercise lightly to help stimulate a bowel movement, poop, and then exercise hard.
  • Experiment with training at different times of the day. Perhaps morning exercise, after having had a bowel movement, is preferable to an afternoon workout, at which time the intestinal tract has accumulated daytime food and fluids.
  • Choose more foods that tend to be naturally constipating, such as bananas, white bread/bagels, white rice, and pasta.
  • Exercise with a bathroom nearby, such as at a gym.
  • Design your running route to include a bathroom, such as a gas station, fast food restaurant, or a friend's house.
  • Before and during exercise, visualize yourself having no intestinal problems. A positive mindset (as opposed to useless fretting) may help control the problem.

As your body adjusts to exercise, your intestines may resume standard bowel patterns. But this is not always the case, as shown by the number of experienced runners who carry toilet paper with them while running.

The bottom line: You are not alone with your concerns. Yet, your body is unique and you need to experiment with different food and exercise patterns to find a solution that brings peacefulness to your exercise program.

Nancy Clark, MS RD CSSD (Board Certified Specialist in Sports Dietetics) counsels casual and competitive athletes in her private practice at Healthworks, the premier fitness center in Chestnut Hill MA (617-383-6100). Her Sports Nutrition Guidebook, new Food Guide for Marathoners, and Cyclist's Food Guide are available at Also see for information about her online workshop.

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