FODMAP foods are foods that contain certain types of carbohydrates. They include sugars that can cause symptoms in the digestive systems of susceptible individuals. Studies have shown eating a diet low in FODMAP foods can help improve symptoms of irritable bowel syndrome.

FODMAP stands for ‘fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.’

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11% of the world’s population, according to a report from Clinical Epidemiology.

In this article, we look at the benefits of a low FODMAP diet, how one works, and what the research says.

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A low FODMAP diet may help manage symptoms of IBS.

A team of researchers from Monash University, Melbourne, Australia, developed The Low FODMAP Diet. The group, led by Peter Gibson, was the first to prove that low FODMAP diets improved IBS symptoms.

The diet plan classifies FODMAP foods as high and low. It recommends that people with IBS avoid high FODMAP foods, and choose low FODMAP foods as their daily staples.

It is important to note that serving sizes can also change how well a person tolerates a specific food. For example, a large amount of a low FODMAP food could turn it into a high FODMAP food.

Low FODMAP foods, which people can eat more liberally than medium and high FODMAP foods include:

  • Vegetables: Lettuces, carrot, chives, cucumber, fennel, eggplant, broccoli (heads or whole), zucchini, green beans, and baby spinach.
  • Fruits: Strawberries, pineapple, grapes, oranges, and kiwifruit.
  • Proteins: Chicken, beef, turkey, cold cuts, lamb, tofu, and eggs
  • Fish: Crab, lobster, salmon, tuna, and shrimp.
  • Fats: Oils, pumpkin seeds, butter, peanuts, macadamias, and walnuts.
  • Starches, cereals, and grains: Potatoes, gluten free bread, quinoa, brown rice, tortilla chips, and popcorn.

High FODMAP foods to avoid, include:

  • Vegetables: Garlic, asparagus, onions, mushrooms, beans, shallots, and scallions.
  • Fruits: Blackberries, watermelon, prunes, peaches, dates, and avocados.
  • Meats: Sausages, breaded meats, battered meats, and meats served with garlic or onion-based sauces and fillings.
  • Fish: Breaded fish, battered fish, and fish served with garlic or onion-based sauces.
  • Fats: Almonds, cashews, pistachios, and avocado
  • Starches, cereals, and grains: Beans, lentils, wheat, and gluten-based bread, rye, muffins, pastries, and pasta.

When a person knows the difference between high and low FODMAP foods, it makes it more straightforward for them to incorporate them into a diet. Both categories contain a wide range of food groups.

It is essential to talk to a doctor or dietitian before starting a low FODMAP diet. Doctors do not typically recommend this diet plan for long-term use, as it eliminates some essential, nutrient-rich foods.

However, many FODMAP foods are prebiotics, which means they support good gut bacteria.

Anyone with an IBS diagnosis who is experiencing the following symptoms might benefit from a low FODMAP diet:

  • continued gut symptoms despite lifestyle and diet changes
  • no response to stress management practices
  • no symptom relief even after removing trigger foods, such as dairy, coffee, alcohol, and spicy foods

Read about different coping strategies for IBS.

Several studies support low FODMAP diets for managing IBS symptoms.

One 2014 clinical trial compared the effects of low FODMAP diets in people with and without IBS. The study authors found that IBS symptoms improved in the low FODMAP group within a week of implementing the diet.

People saw improvements with abdominal pain, bloating, stool consistency, and flatulence.

One 2016 report in Clinical and Experimental Gastroenterology, found that up to 86% of people with IBS saw improvements in their symptoms while on a low FODMAP diet.

One current 2017 report found that low FODMAP foods provide benefits for people with IBS. It also found that certain strains and doses of probiotics may be beneficial, though more research is needed to identify the best options.

Another 2017 review concluded that low FODMAP diets offer favorable results for IBS symptoms but did not find that FODMAP diets are superior to conventional diet plans for IBS.

It is important to note that low FODMAP diets are restrictive and should be temporary.

A low FODMAP diet involves three phases:

  • Elimination: In this phase, which can last from 3–8 weeks depending on a person’s response to the diet, a person eliminates all high FODMAPs from their diet.
  • Reintroduction: Once the elimination phase is over and a person’s symptoms have returned to baseline or are significantly improved, they can start reintroducing FODMAP foods into their diet one at a time, about every 3–7 days. This can help a person identify which foods trigger their symptoms.
  • Maintenance: The maintenance phase involves returning to a regular diet as far as possible, limiting only the FODMAP foods that cause IBS symptoms. Eventually, some people may be able to incorporate all or most FODMAPs back into their diet without symptoms.

Studies show that symptoms can continue to improve for a long time after reducing FODMAPs in the diet and even after reintroducing some of them. However, people should continue to avoid the FODMAP foods that trigger their symptoms.

Useful resources for information about low FODMAP diets and specific foods to include and remove in a low FODMAP diet are the International Foundation for Gastrointestinal Disorders and the Monash University app.

Many other sites provide low FODMAP recipes and tips.

People with IBS experience a group of symptoms at the same time but do not appear to have evidence of damage or disease in the digestive system.

IBS causes the following symptoms:

  • abdominal discomfort, or pain in the abdomen
  • bloating and gas
  • a feeling that bowel movements are incomplete
  • an inability to empty the bowels
  • constipation
  • diarrhea
  • indigestion
  • nausea

Researchers do not know the exact cause of IBS. People with IBS can relieve symptoms through diet changes, medication, stress management, behavioral therapy, and various alternative therapies.

A low FODMAP diet may help improve symptoms of IBS, but not everyone responds well to this diet.

Anyone interested in starting a low FODMAP diet should talk to their doctor or a dietitian regarding the benefits and risks.