Should I try a Low-FODMAP diet?

By Danielle Staub, MS, RD, CDN
Registered Dietitian, Division of Digestive Disease

Let me introduce to you FODMAPs, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. FODMAPs are a group of small chain carbohydrates found in a wide range of everyday foods, including apples, milk, wheat, barley, rye, and even garlic and onion. In some people, FODMAPs are poorly absorbed in the intestine and can cause unpleasant symptoms of IBS such as bloating, gas, altered bowel habits, and abdominal pain. The low-FODMAPs diet is one of the hottest topics in digestive health since it takes a food based approach to managing these challenging symptoms and may even be effective in other digestive disorders.

What is the low-FODMAP diet?

The low-FODMAP diet is an elimination diet that involves removing high-FODMAP foods for 4-6 weeks to assess if these foods are triggering your GI symptoms.  It is not meant to be used long-term and is rather meant to help determine your personal dietary triggers. After the elimination phase, you can slowly re-introduce FODMAPs one group at a time to assess your tolerance to various FODMAP containing foods. Most people will find they only need to restrict some high FODMAP foods, for example you may be highly reactive to garlic and onions (fructans), but can tolerate a serving of pear (fructose) without difficulty.

The science behind FODMAPs

The low-FODMAPs diet was created in 2005 by researchers at Monash University in Australia. It is based on detailed analysis of foods using their lab to identify and quantify FODMAPs in foods.  FODMAPs are thought to trigger symptoms by way of two mechanisms. 1: They are very small carbohydrates and can pull water into the small intestine, contributing to diarrhea. 2: FODMAPs are rapidly fermented (they are fast food for the bacteria in your gut), which can produce gas, bloating, abdominal pain, and cramping.  The combination of gas and water in your intestine produced by these FODMAPs can alter movement of the food in the intestine and contribute to diarrhea or constipation. The low-FODMAP diet is proven to help alleviate symptoms in three out of four IBS sufferers. Sounds pretty good, right?!

Is it right for me?

If you have persistent gastrointestinal symptoms, a low-FODMAP diet may help, however it is important that you first consult with your doctor and dietitian.  Keep in mind that individual tolerance to FODMAPs varies greatly and this approach may not be effective for everyone.  My personal opinion is that when medically appropriate, the low-FODMAPs diet is a fantastic tool to try and many patients have found great relief after doing this diet correctly.

Your gastroenterologist should rule out other intestinal conditions, such as celiac disease, and may also ask you to take a breath test to rule out SIBO (small intestinal bacterial overgrowth), lactose and fructose intolerance.  Since the low-FODMAP diet can be very restrictive, expert guidance and support is essential and can significantly improve patient outcomes. It is also important to reiterate that this diet is not meant for long-term use since it eliminates important nutrient-rich foods and may reduce beneficial gut bacteria.

Examples of low and high FODMAP foods

*This is not a complete list 
*Adapted from Monash University,