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What The Heck Is FODMAP—And What Do They Mean For Runners?

Registered Dietitian Natalie Rizzo explains what FODMAPs are and how they impact runners' diets.

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If stomach issues are a common occurrence during many of your runs, you may want to consider a likely culprit—FODMAPs. If you’re thinking, What the heck are FODMAPs?, you’ll be surprised to learn that they are carbohydrates that might be causing some gastrointestinal distress. Many runners with irritable bowel issues, and even some without, are adopting a low-FODMAP diet to help curtail their digestive issues. Here’s everything you need to know about this low-FODMAP trend and whether it’s right for you.

Related: Three Truths About Gluten You May Not Know


FODMAPs are a certain group of poorly digested carbohydrates. The term FODMAP may sound scary and scientific, but it’s actually an acronym for different types of carbs. Here’s the breakdown:

  • F = Fermentable carbs that are quickly digested by bacteria to produce gas
  • O = Oligosaccharides, otherwise known as fibers found primarily in garlic, wheat, onions and beans
  • D = Disaccharides, specifically milk sugar, otherwise known as lactose
  • M = Monosaccharides or fructose, which is not always well absorbed
  • And
  • P = Polyols, or sugar alcohols, such as sorbitol, mannitol and xylitol found in gum and sports bars

According to Registered Dietitian and Digestive Health Expert Kate Scarlata, RDN, “In individuals that are sensitive to them, FODMAPs are quickly fermented by gut microbes and pull water into the gut, causing gas, bloating, cramping, diarrhea or constipation.”

FODMAPs And Runners

Although it’s unpleasant to talk about bathroom stuff, we have probably all heard the term “runner’s trots.” In simple terms, this usually means running-induced diarrhea, and it happens more frequently that you might like to admit. “During intense exercise, blood flow moves from the intestine to the working muscles, heart and lungs, which can result in diarrhea and cramps,” Scarlata said. She believes that the abundance of carbs, including FODMAPs, in the runner’s diet may be to blame. “One case study revealed consumption of FODMAPs in one athlete to be 11 times more than an athlete with a low FODMAP diet.”

The Low FODMAP Diet

A study of more than 900 athletes found that 55 percent of them actually eliminate at least one high FODMAP containing food, with 83 percent reporting improvements in digestive issues. The same researchers also published a case study which found a short-term low FODMAP diet was an effective strategy for reducing exercise-induced gastrointestinal distress. “When I work with athletes, I do not typically put them on a full low FODMAP elimination diet but rather review their diet and symptoms and adjust their FODMAP intake accordingly,” Scarlata said. She reports that lactose, excess fructose and polyols cause diarrhea, while oligosaccharides usually result in gas and cramping. Depending on the athlete’s symptoms, it may be more beneficial to reduce one type of FODMAP, rather than all of them. “It is best that the athlete work with a FODMAP knowledgeable registered dietitian to guide them through an individualized approach,” Scarlata added. “I find most athletes just need to cut back on their FODMAP intake rather than be super strict with the diet.”

Low FODMAP Foods

If your head is spinning with words like oligosaccharide, let’s break down what all of this means for your food choices. Here are some great low FODMAP foods to incorporate into your fueling plan:

  • Starches: rice, gluten-free pasta, baked potatoes and quinoa
  • Proteins: eggs, chicken, fish, turkey, beef and pork
  • Dairy: lactose-free yogurt and lactose-free milk
  • Fruit: cantaloupe, strawberries, blueberries, kiwi fruit and pineapple
  • Hydration: a sports drink made with sugar
  • Post-workout refuel: ProNourish, a well-tolerated low FODMAP certified nutritional drink. It contains vitamins, minerals, 15 grams of protein and low FODMAP carbs.


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