Do you suffer from pesky GI symptoms that seem to wax and wane sometimes, but flare up before a big race? It’s possible that FODMAPs are contributing to the problem. If you’ve never even heard of them, here’s a crash course. “FODMAP is an acronym for Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols,” says EA Stewart, RD, CLT.

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

The Most Common FODMAP Foods

Some foods high in FODMAPs that you may regularly encounter during any trip to your local market are apples, pears, watermelon, cauliflower, garlic, onions, cashews, and even honey, believe it or not. “Honey is high in fructose,” Stewart explains, “so it can be problematic for some people in moderate to large amounts over a tablespoon, but it’s usually okay in smaller amounts, like 1 teaspoon.” So it’s still more than safe to add a squeeze to your tea without risking stomach issues.

Other high FODMAP foods, according to Harvard Medical School, include lactose, because it’s not easy for most people to break down and digest. Most dairy products, such as 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 this is no surprise, but beans and legumes like chickpeas, lentils, kidney beans, and soy products can contribute to uncomfortable GI symptoms due to high FODMAPs. 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 high in FODMAPs may cause anyone to be riding the struggle bus 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. This extra gas and water can lead to abdominal pain and discomfort in people who are especially sensitive to their effects,” Stewart says. 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 percent sure why certain athletes struggle with IBS and IBD more than others. “While most studies show athletes have the same incidence of IBS as the general population (about 10 percent), one recent study using an older diagnostic tool called the Manning criteria, suggested up to 23 percent of athletes may have IBS,” Stewart says. The study found that an elimination diet, and then reintroduction of what low FODMAP foods caused the least gastric distress into the diet, helped athletes find relief from their IBS symptoms.

Research has also found that many athletes’ high-protein, lower fiber diets (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.

Even if athletes don’t have IBS specifically, they might get pre-race jitters leading up to an endurance event causing uncomfortable GI symptoms. It might be wise to lay off the high-fiber foods about 3 days before the race, Stewart advises. Of course you’ll still want to carb load before the race, and there are plenty of carbs that are lower in FODMAPs for your stomach, like brown rice, quinoa, potatoes, oranges, and kiwi.

Benefits For Athletes Who Follow a Low FODMAP Diet

A number of studies, including one published this year in the Journal of the International Society of Sports Nutrition, are showing evidence that a short-term low FODMAP diet 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. More research is showing that lowering FODMAPs can reduce the pesky GI effects of IBS.

Another recent study recommends that a short-term elimination diet like low FODMAP might help bowel issues in athletes. For example, eliminating something like foods high in lactose, which have proven to be inflammatory for athletes to digest, may make a positive difference in their upper and lower GI tract health.

What To Remember About Following a Low FODMAP Diet for Athletes

If you’re an endurance athlete with gut issues, it might be worth trying a low FODMAP dietary regimen, but remember that it should only be temporary. “Most of my clients try the diet for about four weeks, which should be enough time to know if the diet is working,” Stewart explains. “After that, and assuming a low FODMAP diet has helped with GI symptoms, it’s time to start slowly reintroducing higher FODMAP foods back into the diet,” she adds. 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, stay 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 help matters.