What are FODMAPs?

Written by: Emily Russo, MS, RD, CDN

What is FODMAPs?

Wondering what a FODMAP is? Though it sounds like a geographical term (spoiler alert!) it’s actually a nutritional acronym. In this FODMAP 101 we will review the science behind FODMAPs, why people are trying to avoid them, and if it’s an effective strategy for the management of IBS.

As a dietetic intern in 2009, I learned about a new treatment for Irritable Bowel Syndrome (IBS) called the Low FODMAP Diet. At the time it was so different than anything I had seen before, especially because at first glance the foods on the diet seemed quite disconnected from one another.

Understandably, it was complicated for patients to follow. The dietitian I worked under was frequently clarifying their FODMAP-related questions and it was overwhelming just to observe.

Given the complexity of this diet, I never imagined I would hear about it outside the confines of a dietitian’s office. But, surprisingly, over the past few years I have received more and more questions about FODMAPs. Low FODMAP cookbooks are even popping up on store shelves.

Though I’m surprised by its increasing popularity (but then I recall how many other medical diets turned mainstream), I think it’s worthwhile to understand what FODMAPs are really all about.

This post is intended for general information purposes. It is not intended to replace one-on-one counseling with a medical professional.

First, what is IBS?
IBS is a medically diagnosed condition that is identified through exclusion. Meaning, extensive testing has been done to rule out other GI conditions. This includes, but is not limited to Celiac Disease, Irritable Bowel Diseases (Crohn’s Disease or Ulcerative Colitis), and Diverticulitis, which all present with similar symptoms.

I’ve seen varying statistics on this, but on average IBS afflicts 10-20% of the adult population in developed countries.

What does the acronym FODMAP stand for?
Fermentable – the process by which undigested carbohydrates produce gas
Oligosaccharides – fructans and galacto-oligosaccharides such as pomegranate, dates, prunes, onion, garlic, and legumes just to name a few
Disaccharides – lactose found in dairy products such as milk, yogurt, and ice cream
Monosaccharides – specifically foods that have a higher ratio of fructose to glucose, like apples, cherries, pears, and in sweeteners such as honey
Polyols – sugar alcohols found naturally in stone fruits and mushrooms as well as food additives in chewing gums or mints

Though these words sound complicated, the concept is straightforward. They are all short-chain carbohydrates that can’t be completely digested or absorbed in the intestines. As a result, they are fermented and gas is produced. This is a normal, painless process for most people. But for those with IBS, it can be extremely uncomfortable.

How do I know exactly what foods to avoid from the FODMAP list?
Within each FODMAP category above, there are dozens of foods that need to be eliminated. It is too extensive to name each one here.

When dietitians work with clients or outpatients, they provide comprehensive lists of what foods to avoid and why, and Monash University has a convenient app which outlines all foods that are high or low in FODMAPs.

This is not an endorsement to try this elimination diet on your own, even with these resources as guides; however, the website and app can provide more support and information if you are curious.

What are the steps to follow in the Low FODMAP Diet?
Step 1: Eliminate all foods on the FODMAP list for 2-6 weeks. This includes examining food labels and avoiding any traces of FODMAP foods.
Step 2: Once symptoms resolve, reintroduce food groups from the FODMAP acronym one at a time to assess which specific food group may be the culprit (if there is one).
Step 3: Use this information to develop a more long-term dietary strategy.

Where did this Low FODMAP Diet come from?
The original research studies came out of Monash University in Melbourne, Australia during the early 2000’s. Since then there have been studies conducted all over the world.

Does a Low FODMAP Diet work for everyone with IBS?
Monash University research has shown that approximately 75% of people with IBS who try the Low FODMAP Diet along with education and frequent coaching from a registered dietitian report improvement in symptoms.  As a reminder, the intention of the diet is not to cure IBS, but to help people live more comfortably with it.

In saying that, not every study had the same results, and there were plenty of participants in all studies who did not feel better on this diet. 

Research has shown the best results occur when under the supervision of a registered dietitian who is familiar with this approach. Use the Academy of Nutrition and Dietetics search system to find a qualified registered dietitian near you (they even offer Telehealth appointments).

Why doesn’t a Low FODMAP Diet work for everyone with IBS?
Here are some common reasons why this strategy may not be successful:

  • It is difficult to follow, and so FODMAP foods are often eaten unknowingly.
  • For those with history of disordered eating, elimination diets can be triggering, and may not be appropriate to try.
  • The stress of following this elimination diet can worsen IBS symptoms.
  • IBS symptoms can be caused by something unrelated to this food list.

What are other well-established treatment strategies for IBS?
Stress Management (such as hypnotherapy, meditation, sleep, acupuncture, and acupressure); Physical Therapy (such as exercises or massage); Medical Therapy (like medications prescribed by a GI physician).

Many of these interventions and strategies have been shown to be equally effective on IBS symptoms as the Low FODMAP Diet.

Is the Low FODMAP Diet healthy to follow even if I don’t have IBS?
This is not a “healthy” diet and it eliminates many foods that provide us with health benefits. For example, many fruits and vegetables that offer us beneficial fiber, fluids, and vitamins are not included in the Low FODMAP diet.

Plainly, this is a short-term dietary strategy to ease symptoms for those with IBS.

Bottom Line on the Low FODMAP Diet
This is one of many strategies to help with symptom relief in those who have IBS. The Low FODMAP Diet is challenging to follow and is best done under the supervision of a registered dietitian who is familiar with the diet.

There are other strategies to help manage IBS besides the Low FODMAP Diet, and it is not an appropriate intervention for everyone. It is not a “healthy” diet, it is not intended for weight loss, and it should not be recommended to anyone besides this specific population.

Every individual is unique and what may work for one person may not be helpful for someone else. Speak with your physician to help navigate the best course for you.

If you have questions, or want to share your experience with FODMAPs, we would love to read your feedback in the comments section below!

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  1. Gina Plain

    Excellent explanation for the layman! Thank you. I had never thought of trying this diet but it reminds me of how many people also think going on a GF diet is healthy. My husband has celiac so for him it’s not a choice. I find the educational aspect of the Fountain Ave Kitchen to be a great addition!