What Is the FODMAP Diet?

Arielle Leben M.S., R.D., C.D.N., a nutrition specialist at the Inflammatory Bowel Disease Center at NYU Langone Health in New York City, explains how a low FODMAP diet may help people with ulcerative colitis.

The FODMAP diet stands for fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols. A really long way of saying short-chain carbohydrates, which are sugars and fibers that are commonly malabsorbed and can cause symptoms such as gas, bloating, constipation, diarrhea, abdominal discomfort. Some people get some of them and some people experience all of them.

Research has actually shown that the FODMAP diet can be effective in patients with IBS and IBD who are still experiencing symptoms, meaning that perhaps you go to your doctor, you have a colonoscopy, they tell you that everything looks pretty well controlled, everything looks good, but you're still symptomatic. Then FODMAP foods might actually be worthwhile to reduce and see if they can help the symptoms that you're having.

Basically, this elimination diet in its strict form is not recommended for patients who have active disease. If you decide to follow the diet, it's done in three parts. The first part is the elimination phase, which is short term, and that's roughly about two to six weeks. If you notice, some benefit while the elimination phase is going on, you proceed to the reintroduction phase. That's the phase where you do some testing, and you try to figure out what your trigger foods are.

Then the final stage, which often gets overlooked, but in my opinion is most important. This when you take the information that you got from the reintroduction phase and apply it to your long-term diet. What are your limitations long-term? Odds are you can add back a lot of the high FODMAP diet, but you might have some restrictions in terms of food choices. More often, though, it's the quantity of the high FODMAP foods than the foods themselves.