The Low FODMAP Diet: Can It Ease Your IBS Symptoms?

Diarrhea, indigestion, bloating, abdominal pain. If changing your diet could ease the constant discomfort of living with irritable bowel syndrome (IBS), would you try it? Over the past 15 years, the low FODMAP diet has been recognized by dietitians and integrative medicine docs as an effective tool for identifying trigger foods and helping patients find relief. But what are FODMAPs, and how can limiting them in your diet help your symptoms? Here’s what you should know about the low FODMAP diet for IBS — plus tips for trying it on your own.


FODMAPs (an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are carbohydrates present in many of the foods we commonly eat. Remember learning about osmosis in middle school science? FODMAPs are “osmotic,” which means they pull water into the intestinal tract. When eaten in excess, they might not be digested or absorbed well. FODMAPs are also fermented more quickly than other carbohydrates, which could lead to rapid gas production.

“High FODMAP foods are not ‘bad’ foods, but may be too much of a good thing at times.”

Food sources of FODMAPs include those with excess fructose, such as honey, apples, mango, pear, watermelon and high fructose corn syrup; fructans, such as artichokes, garlic, onion, wheat, rye and barley; lactose in milk, ice cream, yogurt and soft cheeses; “galacto-oligosaccharides,” such as legume beans, lentils and chickpeas; and “polyols,” such as apples, apricots, avocados, cherries, nectarines, plums and mushrooms.

If you’re thinking this list contains some pretty healthy foods, you’d be right.  “I make sure people understand that high FODMAP foods are not ‘bad’ foods, but may be too much of a good thing at times,” says Patsy Catsos, MS, RDN, LD, a dietitian in private practice in Portland, Maine, author of IBS—Free at Last! and co-author of IBS-Free Recipes for the Whole Family.

 Identify trigger foods and find relief with a six to eight week elimination diet.

Chart: Patsy Catsos IBS—Free At Last!

The Benefits of a Low FODMAP Diet for Your Gut

 So what do FODMAPs have to do with your IBS? The combination of increased fluid in your intestines, along with the extra gas produced through fermentation, can lead to bloating and abdominal distension, as well as changes in motility, or contractions of the muscles that mix the contents of your gastrointestinal tract, says Catsos. This can lead to bouts of IBS symptoms that can take hours to kick in, since the FODMAPs have to make their way through the stomach and into the intestines before they can start stirring up trouble.

The goal of the Low FODMAP diet is to see if symptoms improve after eliminating FODMAPs and if so, to slowly discover which foods are an issue for the individual. And it’s pretty effective: In one 2014 study in the journal Gastroenterology, researchers from Monash University in Australia found that following a low FODMAP diet can help reduce GI symptoms in people with IBS. Study participants also experienced less bloating, pain and passing of wind (yes, that means they farted less) after 21 days on the diet.

Melinda Ring, MD, executive medical director at the Osher Center for Integrative Medicine at Northwestern University, says she has seen her own patients experience these benefits. “It allows them to identify foods that, while healthy in many ways, are difficult for their own gut to digest.”

What About IBD?

While people often get IBS and IBD confused, they’re two very different disorders. They share many of the same symptoms, such as diarrhea and abdominal pain and cramping, but Crohn’s disease and ulcerative colitis are chronic inflammatory conditions that can’t be treated with lifestyle changes alone.

Unlike IBS, very little research has looked directly at the impact of FODMAPs on people with IBD, says Catsos, and it would be unrealistic to expect all IBD patients to see results on a low FODMAP diet or for the diet to completely eliminate symptoms during a flare.

“Some of those symptoms are a direct result of the disease process and may have nothing to do with food,” she says. “But to the extent that high FODMAP foods were aggravating symptoms, cutting them from the diet might reduce them.”

A treatment plan for IBD will first address the inflammatory and autoimmune components of the disease, which involves both conventional therapeutic approaches as well as diet, supplements and functional medicine, says Ring.

Beat the Bloat: Getting Started on a Low FODMAP Diet

Want to give it a try yourself? First things first: consult with your doctor before starting any new eating plan. In addition, use resources prepared by knowledgeable nutrition professionals, says Catsos, and work with a registered dietitian if you have access to one. (Many insurance plans cover RD visits, so look for an in-network dietitian who has experience working with IBS or IBD patients.)

“While the [low] FODMAP diet may not provide 100 percent relief, it can be life changing for many IBS sufferers.”

Catsos recommends the Monash University Low FODMAP Diet app ($7.99), which features a searchable FODMAP list, plus recipes, so you can plan your meals right and calculate your FODMAPs throughout the day. “Don’t over restrict your diet,” she says. “Look first at your beverages: A common mistake is replacing fluids lost from diarrhea with high FODMAP choices such as fruit juice, smoothies, milk or soft drinks.”

After about six to eight weeks, you’ll be able to start adding in small amounts of FODMAP-containing foods to see which foods you can tolerate, and which ones send your intestines into overdrive.

“Patients can use the diet as a way of figuring out what their trigger foods are, and at what dose,” says Ring. “While the [low] FODMAP diet may not provide 100 percent relief, it can be life changing for many IBS sufferers.”

Article originally published March 29, 2016.