If your digestive system seems to have a mind of its own—fine one day, unpredictable the next—the problem may not be what you’re eating, but how your gut responds to certain foods. Doctors call it irritable bowel syndrome.
Researchers have discovered that a surprising group of carbohydrates found in everything from apples and onions to dairy and wheat can trigger bloating, gas, diarrhea, constipation and that dreaded race to the restroom. The good news? They've also discovered a way to finally put you back in control.
Key Takeaways
- Certain carbohydrates may trigger IBS symptoms. FODMAPs are fermentable carbohydrates that can contribute to bloating, gas, abdominal discomfort and changes in bowel habits in susceptible people.
- The restrictive phase is temporary. After an initial period of reducing high-FODMAP foods, foods are systematically reintroduced to discover which ones actually cause problems.
- The ultimate goal is personalization. Rather than avoiding a long list of foods forever, the goal is to create the least restrictive diet that keeps symptoms under control.
Irritable bowel syndrome (IBS) is a vexing condition.
In some people, it leads to very frequent diarrhea. In others, it creates chronic constipation. Or, in the worst of both worlds, IBS can cause you to alternate back and forth between both -- with bloating, nausea, stomach pain and intestinal gas thrown in just to keep it interesting.
Researchers have long struggled to explain what causes IBS much less how to keep it under control. Until now, that is. Researchers now think they have an answer to this intestinal dilemma – a regimen with a strange name: the FODMAP diet.
I’m not going to tell you this diet is easy to follow. But there’s solid evidence that it works.
The ins and outs of FODMAP
The FODMAP diet is designed to fend off IBS by eliminating foods that contain what are called fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPS for short).
Those are complicated names for certain carbohydrates found in many fruits and vegetables that stimulate the overgrowth of problematic bacteria in the large intestine. Those multiplying bacteria, even though they also produce health benefits when they’re at their proper levels, are believed to cause the digestive issues of IBS.
However, the FODMAP diet is not a panacea. It clears up IBS symptoms in about 50 to 80 percent of the people who try it (different studies come up with different numbers). The downside is that the diet rules out many fruits and vegetables normally considered healthy. For instance, apples are high in FODMAPs and have to be restricted, while grapes are relatively low.
According to researchers, the initial phase of a FODMAP diet, where all FODMAPs are severely reduced, should not be followed for very long because it is too limiting. Instead, after two to six weeks, they tell dieters to reintroduce some foods with FODMAPs to see which ones can be tolerated without suffering IBS symptoms.
But if you can stick with this diet through its three phases, the results of research on it are impressive. For instance, a study at the University of Michigan found that in a six-week trial, 61 percent of the IBS sufferers in the research had “major” improvements in their bowel problems. In particular, bloating, diarrhea and the urgency of bowel movements were significantly reduced.1
If you frequently have the experience that you have to find a restroom RIGHT NOW, it’s worth trying this eating plan, considering it works for well over half the people who do.
"Our next step will be to more precisely determine the underlying chemistry of how and why particular foods can yield dramatically different results for different people,” says researcher Shanti Eswaran.
Following the Diet
As I said before, sticking to the FODMAP diet, in any of its phases, for any length of time can be challenging. An important point to remember – you can’t completely eliminate FODMAPs from your diet, you can only greatly reduce them. That’s because there’s a small amount of FODMAPs in virtually every fruit and vegetable. So the diet really reduces your intake of FODMAPs. It doesn’t entirely do away with them.
Monash University in Australia has done a great deal of research into FODMAPs and it’s the major source of information about it. Scientists there have created a smartphone app that supplies a constantly updated list of foods that are allowed and not allowed.
The Monash app also includes rankings of foods as low, moderate or high in FODMAP content, plus recipes and information about IBS.
If you want to try the diet without the app, lists of foods and their FODMAP status can be found at these sites:
- This provides a list of foods high in FODMAPs
- This is a list of low FODMAP foods.
According to the Monash researchers, the diet should follow three phases2
- Two to six weeks of only eating very low FODMAP foods.
- Eight to twelve weeks of introducing new FODMAP-containing foods carefully, one at a time, to see which ones you can tolerate.
- Thereafter maintaining a diet personalized for you that omits your problem foods.
Many people find better success with this program if they are also counseled by a knowledgeable dietitian. But if you are plagued with IBS, it’s worth a try.
Summary
The low-FODMAP diet is a structured eating approach designed to help people with irritable bowel syndrome (IBS) identify foods that trigger digestive symptoms. FODMAPs are certain fermentable carbohydrates that can contribute to gas, bloating, abdominal discomfort, diarrhea and constipation in sensitive individuals. Research suggests that many people with IBS experience meaningful symptom improvement on a low-FODMAP diet. However, the most restrictive phase isn't intended to be permanent. The diet typically progresses through three stages: temporarily reducing high-FODMAP foods, systematically reintroducing them to identify individual triggers, and creating a personalized long-term diet that allows as much variety as possible while minimizing symptoms.
Frequently Asked Questions
What does FODMAP stand for?
FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols—types of short-chain carbohydrates that can cause digestive symptoms in some people.
Can a low-FODMAP diet help IBS?
Research suggests that a low-FODMAP approach can improve symptoms for many people with IBS, although individual responses vary.
Do you have to avoid high-FODMAP foods forever?
No. The initial restrictive phase is temporary. Foods are then gradually reintroduced to determine which FODMAPs and amounts an individual can tolerate.
What foods are high in FODMAPs?
High-FODMAP foods can include certain fruits, vegetables, grains, dairy products and sweeteners. Portion size also matters because FODMAP content can change depending on how much you eat.
Should I try the low-FODMAP diet on my own?
Because the diet can be restrictive, guidance from a registered dietitian knowledgeable about IBS and the low-FODMAP approach can make it easier to maintain adequate nutrition while identifying triggers.
