Diarrhea during long runs—HELP!!!!

Posted on 24-02-2018 , by: Nancy Clark , in , , , 0 Comments

Nancy, I have a bad problem during my long runs: Diarrhea!!! I am training for a marathon and I am afraid to eat beforehand. If I don’t eat anything, I run out of energy. HELP!!!!  A very frustrated marathoner

Dear Marathoner, I can hear your frustration—and your fear of fecal urgency. You want to be able to trust your body.

I have a couple of suggestions.

1) Below is a food chart you might want to keep. You could write down what (and at what time) you eat. Then, keep track of your episodes of diarrhea. Using a colored pen, mark on the chart the times you have mild (D), moderate (DD) or miserable (DDD) diarrhea. In the comments section, note 1) the type of workout (long run, intervals, race, etc.); 2) if you felt unusually stressed that day (S, SS, SSS- for medium, high, very high stress) 3) if you are a women, the stage of your menstrual cycle (a common trigger for diarrhea).

Meal Mon Tue Wed Thur Fri Sat Sun

Hopefully, you will see a pattern of some sort. You can then experiment by taking out one food, let’s say onion, for three or four days and observe any bowel differences. Then, add back that food, and even double-dose it, to see if the problem returns. In the comments section of the chart, write down the experiment of the day, and if it had any noticeable effect.

The dose is often the “poison”, so once you have pinpointed a potential trigger, continue the experiment to see how much of the trigger food you can tolerate. That is, if apple is a trigger, can you eat an apple at breakfast and then another one at lunch without creating distress?

2). Educate yourself about FODMAPS. FODMAPS are types of fibers found in fruits, vegetables, wheat and sugar-free foods (with sorbitol). Common offenders are apples, onion, garlic, lactose in dairy milk, and fructans in wheat. Kate Scarlata RD has lots of helpful information on her website (www.KateScarlata.com), as well as her new book The Low-FODMAP Diet: Step by Step. The book has 125 recipes, many of which are perfect for carbo-loading.

Research by Dana Lis RD suggests that athletes who experience gastro-intestinal distress can often reduce their symptoms by eating a low FODMAP diet for a few days prior to, let’s say, a long training run or a competitive event.

Hopefully, you will receive benefits by making a few simple food swaps, such as having fewer apples (High FODMAP) and more grapes (low FODMAP). That said, your body is unique to you. You are an experiment of one. You might want to seek help from a registered sports dietitian who can help you resolve the problem. The referral network at www.SCANdpg.org can help you find your local sports RD.

With best wishes for miles of smiles,


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