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FODMAPs, Part 1: What Are They?

Athletes are humans: Although they excel in their sport, they aren’t protected from medical conditions or food intolerances.

Irritable bowel syndrome (IBS) is a chronic medical condition that targets the large intestine. Common IBS symptoms include abdominal pain, cramping, or distension; loose stools, diarrhea, or mucus in the stool; and constipation. Changes to one’s diet can help alleviate IBS symptoms.

Source: FitnessVigil

Exercise-induced gastrointestinal syndrome has been reported to occur in 30-70% of endurance athletes during and after exercise (in the absence of a clinical diagnosis of IBS but presenting with similar symptoms). This is concerning, since these symptoms can negatively impact performance, extend race times, and increase training- and race-related anxiety.

Manipulating an athlete’s food and beverage intake before and during key workouts has been shown beneficial in lessening symptom severity for ultraendurance athletes, Ironmen, and even 5-kilometer recreationally active runners.

Regardless of if an athlete has IBS or not, yet is presenting with any of the above symptoms, sometimes the issue isn’t one food, but a family of foods, that may be troublesome to their gut.

A few of those families fall under the FODMAPs umbrella.

What are FODMAPs?

Major roles of the large intestine are water and salt reabsorption, plus bacterial activity on any passing-by food. However, when these roles are inadequately accomplished, the presence of poorly-digested FODMAPs may lead to havoc.

FODMAPs is the abbreviated term for a family of short-chain carbohydrates that span a wide range of foods—including fresh, processed, and healthful options.

Spelled out, FODMAPs stands for:

  • F = Fermentable

  • O = Oligosaccharides [i.e., fructans and galacto-oligosaccharides (GOS)]

  • D = Disaccharides (e.g., lactose)

  • M = Monosaccharides (e.g., excess fructose)

  • A = And

  • P = Polyols (e.g., sugar alcohols)

A mouthful that doesn’t mean much.

Interpreted into items in our food system, here’s a few examples of what low-, medium-, and high-FODMAPs look like:

Why do FODMAPs Cause Problems for Some People?

When poorly-digested FODMAPs are present in the large intestine, two things can occur:

  1. Water is pulled into the large intestine: The presence of FODMAPs offset the balance between the inside tunnel and the surrounding area of the large intestine. This causes water to be pulled into the tunnel, which is why diarrhea or loose stools may result.

  2. Gas production: Bacteria in the large intestine acts on the FODMAPs, creating gas as a byproduct. This can cause abdominal pain, bloating, distention, and flatulence.

Why Would Someone Follow a Low FODMAPs Diet?

Research supports that those diagnosed with IBS report improvements in symptoms by 74% when following a lower FODMAPs diet. This is important, since a nutrition-focused approach could reduce the dose or entirely remove the need for medications that are typically employed to help control symptoms. It also allows those suffering with IBS to feel an increased sense of control over their symptoms.

Following a lower FODMAPs diet means consuming small amounts of FODMAPs to control IBS symptoms—or IBS-like symptoms in endurance athletes. Avoiding items high in FODMAPs is required to minimize or eradicate symptoms (see above table).

Follow-up blog posts (read part 2 here) will cover the application of beginning FODMAPs, since nuances include the length of time a person would remain on a low FODMAP diet, portion sizes, reintroducing certain FODMAPs, etc.

Further Reading:

Learn more about where to start and what plan works best for your athlete.

Discover more about food brands, where FODMAPs data from the food system comes from, and why the cumulative effect of low FODMAPs may matter.

Foods and beverages marketed to athletes contain FODMAP ingredients. Find out what products contain and are free of FODMAPs.

“The Complete Low-FODMAP Diet” by Sue Shepherd, PhD and Peter Gibson, MD.

Similar to the above table, lists of low-, medium-, and high-FODMAP options are included, plus a variety of recipes. It's my go-to book when counseling symptomatic athletes.

Kate is a leading dietitian and researcher in the area of FODMAPs. Her free resources include a low FODMAPs grocery list.

The university that penned the term FODMAPs, and continues to lead research on the topic, created an app that allows users to filter by FODMAP subgroup. The app has a one-time fee and is a tool I use when counseling.

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