Do you suffer from gastrointestinal (GI) issues that seem to wax and wane sometimes, but flare up before a big race? It’s possible that FODMAPs are contributing to the problem. And if you’ve never even heard of them, here’s a crash course. 

“FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols,” EA Stewart, RD, CLT, says. 

Basically, FODMAPs are carbohydrates and sugar alcohols found in certain foods, including wheat, some legumes, garlic, onion, and certain fibrous fruits and vegetables. These foods are notoriously irritating and difficult to digest for those with bowel issues such as ulcerative colitis and irritable bowel syndrome, Stewart explains. Since endurance athletes tend to suffer from these digestive conditions often, it may be worth following a low-FODMAP meal — even temporarily — for smoother digestion. 

Which Foods Are High-FODMAP?

Some high-FODMAP foods that you may regularly encounter during any trip to your local market are apples, pears, watermelon, cauliflower, garlic, onions, cashews, and even honey.

“Honey is high in fructose, so it can be problematic for some people in moderate or large amounts over a tablespoon, but it’s usually okay in smaller amounts, like 1 teaspoon,” Stewart explains.

So, it’s still more than safe to add a squeeze to your tea without risking stomach issues. 

Related: How Your Gut Health is Impacting Your Performance (and How to Hack It)

Lactose is another high-FODMAP food item, according to Harvard Medical School, because it’s not easy for most people to break down and digest. Most dairy products — milk, yogurt, soft cheeses, and ice cream — fit under the lactose umbrella. Cruciferous veggies including broccoli, artichokes, asparagus, and Brussels sprouts are high in FODMAPs, too. And it's no surprise that high-FODMAP beans and legumes like chickpeas, lentils, kidney beans, and soy products can contribute to uncomfortable GI symptoms. There are also hidden FODMAPs in artificial sweeteners, found in gums, cough drops, and even some yogurts and cereals. Wheat and rye grains are higher in FODMAPs and might also irritate you if you have a gluten sensitivity, but rice, quinoa, and oats are gluten-free and shouldn’t bother you.  

Why FODMAPs Are Generally Difficult For Digestion 

Foods that are high in FODMAPs can cause nearly anyone to struggle digestion-wise, but if you already have any kind of digestive or GI issues (IBS, and any kind of bowel inflammation), your gut will likely be more sensitive.

“High-FODMAP foods are fermented by gut bacteria and draw water into the intestines," Stewart says. "This extra gas and water can lead to abdominal pain and discomfort in people who are especially sensitive to their effects."

The movement in your digestive system (particularly if you have IBS) will either be sped up, causing diarrhea, or slowed down, causing bloating and constipation. 

Athletes and Gut Issues 

Scientists aren’t 100% sure why certain athletes struggle with gastrointestinal issues more than others.

“While most studies show that athletes have the same incidence of IBS as the general population (about 10%), one recent study using an older diagnostic tool called the Manning criteria, suggested up to 23% of athletes may have IBS,” Stewart says.

The study found that eliminating those foods and then introducing low-FODMAP foods that caused the least gastric distress into the meal plan helps athletes find relief from their IBS symptoms. 

Research has also found that many athletes’ high-protein, lower-fiber meal plans (which are traditionally best to follow right before a long race or endurance event) may have a negative effect on gut microbiome diversity. The lack of diversity in gut bacteria could lead to inflammation in the colon, and may lead to IBS as well. 

Related: How Probiotics Can Enhance Your Training and Overall Performance

Even if athletes don’t have IBS specifically, they might get pre-race jitters leading up to an endurance event causing uncomfortable GI symptoms. In that case, it might be wise to lay off the high-fiber foods about three days before the race, Stewart advises. Of course, you’ll still want to consume plenty of carbs before the race. Try choosing from those that are lower in FODMAPs for your stomach's sake, like brown rice, quinoa, potatoes, oranges, and kiwi. 

Benefits for Athletes Who Follow a Low-FODMAP Meal Plan

A Journal of the International Society of Sports Nutrition study shows evidence that a short-term low-FODMAP meal plan can improve symptoms of endurance exercise-related IBS, and may give athletes the ability to be able to train for longer periods of time as a result.  

Additional research even shows that lowering FODMAPs can reduce the pesky GI effects of IBS, while yet another study recommends that a short-term elimination meal plan such as low-FODMAP might help bowel issues in athletes. For example, eliminating high-lactose foods, which have proven to be inflammatory for athletes to digest, may make a positive difference in upper and lower GI tract health. 

What to Remember About Following a Low-FODMAP Meal Plan for Athletes

If you’re an endurance athlete with gut issues, it might be worth trying a low-FODMAP meal plan, but remember that it should only be temporary.

“Most of my clients try the plan for about four weeks, which should be enough time to know if it is working,” Stewart explains. “After that — and assuming a low-FODMAP meal plan has helped with GI symptoms — it’s time to start slowly reintroducing higher-FODMAP foods back into the meal plan."

Related: 4 Ways That Athletes Can Benefit From Fermented Drinks

You’ll then be able to tell which foods have bothered you and which you can better tolerate. 

Other than that, you can amend gut symptoms by controlling your portion sizes, staying away from anything that might have sugar alcohols (like chewing gum and diet sodas), and cutting back on foods that are either fried or high in saturated fat. And, Stewart says, managing your stress and getting quality sleep can only improve your symptoms.