Runner’s Diarrhea – How to Prevent It?

Runner’s diarrhea may occur during or after a long distance run, workout, occasional run, or walk (1) .

Exact cause of runner’s diarrhea is not known, but the following may contribute to it:

  • Up and down moving of intestine
  • Blood moving from the gut to the legs, what switches the gut to the rest mode so existing bowel content can not be digested properly
  • Stress, which may trigger irritable bowel syndrome
  • Dehydration

Prevention of Runner’s Diarrhea

At least TWO DAYS before the run avoid:

  • High-fiber foods like legumes (beans, soy, peas, lentils), cabbage, cauliflower, large amount of cereals, to avoid excessive bloating;
  • Fat-rich foods like pork, bacon, pizza and most of other fast foods, cakes, olives, nuts, chocolate, which are hard to digest and may stay in the bowel for a long time;
  • Dairy;
  • Fructose-rich foods: honey, grapes, apples, pears, mango, stone foods (like peaches, cherries), dried fruits (like prunes, raisins, figs, dates), jams, fruit juices or any fruit product from mentioned fruits; sorbitol (in “sugar free” chewing gum, “low calorie foods”, some carbonated beverages or sport drinks); also avoid other “polyols” (read labels), like xylitol, maltitol, mannitol, isomalt.  For further explanation read about fructose malabsorption.
  • Hot spices, like pepperoni, which may irritate the bowel;
  • Alcohol, because it causes dehydration.

Generally safe foods before running are bread, corn products, rice, pasta, poultry, potatoes, bananas, citruses (lemons, oranges), moderate amounts of green-leafy vegetables, soups and broths.

Picture 1. Marathon runners

At least TWO HOURS before the run:

  • Have a bowel movement, and do not eat anything more until the end of the run.

DURING the run:

  • Drink enough water or sport drinks but avoid hot drinks or drinks sweetened with sorbitol or xylitol, carbonated drinks, caffeine, alcohol.

Drink enough fluid before, during and after the run (1).

Related Articles:


  1. Runner’s diarrhea  (
About Jan Modric (249 Articles)
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