For many people suffering from irritable bowel syndrome (IBS), the low-FODMAP diet can feel like a miracle. If you were plagued with abdominal pain, cramping and bloating, along with diarrhea or constipation (or both) — and frequently afraid to leave the house because you might not be near a toilet when you urgently need one — you would know what I mean. But is the low-FODMAP diet right for everyone?

What is a FODMAP, you ask? FODMAP stands for fermentable oligosaccharides, monosaccharides, disaccharides and polyols. These are types of carbohydrates that are highly fermentable by bacteria and other microbes in your large intestine, or colon. This is fine (even good) for most people, but if you have IBS, when FODMAPs can trigger symptoms once they reach the colon.

FODMAPs include fructose and lactose, the natural sugars found in fruit and dairy, respectively, as well as types of fiber found in wheat, rye, onions, garlic beans, some nuts and many vegetables. Polyols include the common artificial sweeteners sorbitol and xylitol.

Unfortunately, much like the gluten-free diet — which serves a genuine purpose for the small percentage of people diagnosed with celiac disease or non-celiac gluten/wheat sensitivity — the low-FODMAP diet is being coopted for purposes that it wasn’t designed for. And that’s no miracle.

Who’s trying the low-FODMAP diet (but shouldn’t be)?

IBS is now classified as a disorder of gut-brain interaction, which means there’s a disconnection with how your gut and brain are communicating with each other. It used to be known as a functional gastrointestinal disorder, because while it affects intestinal function, it doesn’t damage the intestines or their structure (the good news). But IBS symptoms can significantly harm quality of life (the bad news).

IBS affects about 12 percent of people in the U.S., and women are twice as likely as men to suffer from it. New cases usually happen before age 50, and having a family member with IBS or a history of stressful and traumatic events can increase risk.

The low-FODMAP diet can be attractive to individuals trying to self-diagnose their gastrointestinal symptoms, something that is never a good idea. Many IBS symptoms overlap with symptoms of far more serious (structural) gastrointestinal conditions, including celiac disease, inflammatory bowel disease — which includes Crohn’s disease and ulcerative colitis — and less commonly, colon cancer. While there’s no test for IBS, if symptoms suggest a more serious problem, there is testing for those issues.

Because it restricts so many foods, some people have also been turning to the low-FODMAP diet for weight loss. Odd, because there’s only scant research showing that some people with IBS who follow the diet also lose a small amount of weight.

The low-FODMAP diet may also be appealing to individuals struggling with an eating disorder, either as a cover for their disorder — “I’m only avoiding these foods because I have IBS…really” — or because they truly think they have IBS. However, eating disorders often cause gastrointestinal distress all by themselves. Chronic food restriction, binging, purging, laxative abuse and excessive intake of carbonated beverages and artificially sweetened beverages, gum and foods can all disrupt normal digestion and cause gastrointestinal symptoms, such as the bloating and constipation so common with IBS.

What to consider before trying ANY elimination diet

The low FODMAP diet has been shown to highly effective in relieving symptoms of IBS in published research, and I’ve found that to be true in my own clinical practice. Many of my IBS clients have told me they felt like they got their life back. However it is definitely not for everyone.

If you’re already following a restricted diet due to a pre-existing medical condition, a diagnosed nutritional deficiency, and/or a long history of dieting or disordered eating, you shouldn’t attempt this diet without careful consideration and the close supervision of your healthcare team, including your doctor, gastroenterologist and registered dietitian nutritionist (RDN).

For someone who is at high risk of an eating disorder due to genetics and environment, undertaking an elimination diet — even when otherwise warranted — can be the tipping point.

I had a client a few years ago who working with me on recovery from orthorexia, an unhealthy obsession with eating healthy. She told me she had a possible diagnosis of IBS and had tried a low-FODMAP diet on her own, but stopped because she realized she liked the restrictiveness of it too much and feared it would lead her to a dark place. The good news is that as her diet became less rigid — she had been a strict “clean eater” — her constipation and bloating improved.

3 reasons to avoid the low-FODMAP diet

Here are three major reasons why you don’t want to follow the low-FODMAP diet if you don’t actually have IBS:

  • It’s restrictive. While the elimination phase of this diet is less restrictive than some elimination diets, it requires cutting out many healthy, nutritious foods. If it’s not planned well, it can be low in key nutrients and in fiber, specifically prebiotic fiber, the fiber that our beneficial gut bacteria like to eat.
  • It’s meant to be very temporary. When followed as intended for the treatment of IBS, the diet protocol begins with eliminating all high-FODMAP foods for a few weeks. If this successfully reduces symptoms, then these foods are reintroduced in a very structured, methodical way while watching for any returning symptoms. The goal is to pinpoint which FODMAPs, in what amounts, trigger symptoms, so that the person with IBS can enjoy as varied a diet as possible while still managing their symptoms. I’ve had clients who felt so much better on the elimination phase that they just wanted to stay on it, which isn’t good for long-term health.
  • It’s hard to follow without help. I’ve had clients who thought they were following the elimination diet to the letter, and were mystified when they had a symptom flare up, only to find that they forgot that asparagus is high in FODMAPs, or didn’t realize that there was a lot of garlic in the salad dressing they had at a restaurant. Also, it’s easy to become too relaxed during the reintroduction phase, making it difficult to be sure which FODMAPs are responsible for any symptom flare-ups.

Want more information on my IBS Management Program? You can find that here.

Carrie Dennett, MPH, RDN, is a Pacific Northwest-based registered dietitian nutritionist, journalist, intuitive eating counselor, author, and speaker. Her superpowers include busting nutrition myths and empowering women and men to feel better in their bodies and make food choices that support pleasure, nutrition and health. This post is for informational purposes only and does not constitute individualized nutrition or medical advice.

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