I’m happy to be sharing this article from Alex Mrosczyck-McDonald at Trismarter.com. If you’re serious about racing - these are some of the best guys to talk to. Hope you enjoy!

Can Fiber Wreck Your Race?

We all know that fiber is an important part of our diet, but what exactly does fiber do and can it lead to gastrointestinal (GI) upset during a race?

What is Fiber?
Fiber is the part of a plant that the body cannot digest or use for fuel and is an important part of a diet for numerous reasons.
There are two kinds of fiber, soluble and insoluble. Soluble fiber is absorbed into the body and primarily helps to lower LDL (bad) cholesterol, maintain blood glucose levels as well as aid other metabolic function. Insoluble fiber, as the name suggests, is not absorbed into the body and simply passes through the GI tract adding more bulk and water to the stool, promoting proper bowel function.

According to the American Heart Association soluble fiber has been associated with increased diet quality and decreased risk of cardiovascular disease. Foods high in soluble fiber include oat bran, oatmeal, beans, peas, rice bran, barley, citrus fruits, strawberries and apple pulp.

Insoluble fiber, which is found in whole-wheat breads, wheat cereals, wheat bran, rye, rice, barley, most other grains, cabbage, beets, carrots, Brussels sprouts, turnips, cauliflower and apple skin, can cause lower GI problems on race day. This is not to say that if you don’t eat fiber you will have no waste. You will; it will just be less bulky.

A high fiber diet is an important part of an athletes diet for two reasons: One, it slows digestions of other carbohydrates by prolonging gastric emptying. This increases satiety, and may help prevent overeating, as well as may prevent blood glucose spikes and valleys (i.e. sugar high and crash) which allow the body to receive a steady glucose, which is a better energy source and helps prevent metabolic diseases, such as diabetes. Secondly, insoluble fiber should be incorporated into your diet because it helps to clean out the bowel by maintaining optimal bowel pH as well as remove dead cells and other debris, which in turn can prevent diverticulosis and possibly colon cancer.

Getting the Right Amount of Fiber
Dietary fiber intake among adults in the United States averages about 15 grams. The Institute of Medicine recommends consuming 14 grams of fiber for every 1,000 calories, which, for most, correlates to a daily requirement of 25-35 grams of fiber, although athletes may require more based on a higher caloric diet.

A common problem in triathletes, particularly during longer races, is lower GI distress during competition, particular while running. Every athlete’s body will respond differently to the stress of race day and no single fiber protocol will work for everyone. However, because fiber adds bulk to the stool eating a diet low in fiber for one or two days leading up to a race may help to ward off lower GI problems. If this does not help some may recommend taking an anti-diarrheal agent, such as Imodium prior to or even during the race. However, carefully follow the recommended dosage and do not take more than is suggested on the package.

The bottom line is a daily dose of 25-35g of fiber from a variety of sources is an important part of a healthy diet. However, reducing fiber intake prior to a race may prevent frequent stops on the run course.

Alex Mrosczyck-McDonald is a triathlon associate with Trismarter.com, a 4th year medical student at the University of Vermont, and a member of the Timex Multisport Team with an interest in sports medicine and exercise physiology. He is also a triathlon associate with Trismarter.com. Prior to medical school Alex graduated from Connecticut College in 2003 with an emphasis on both the biological and social sciences, where he was involved with numerous athletic as well as community based activities. He currently lives in Burlington, VT where upon completing medical school he will defer his medical career in order to race as a professional long course triathlete.