Diet and Nutrition

The Low FODMAP Diet and Inflammatory Bowel Disease: Myths and Facts

The Low FODMAP Diet and Inflammatory Bowel Disease: Myths and Facts

Until now, it has been recognized that diet neither causes nor treats inflammatory bowel diseases (IBD) such as Crohn’s disease or ulcerative colitis. However, specific diets have proven to be helpful in alleviating symptoms associated with these diseases. When considering this, it is important to distinguish between a remission state of the disease and an active state of the disease (flare-up).

When in remission, eating a healthy and well-balanced diet rich in fruits, vegetables, and whole grains is recommended. During an active flare-up, it is important to maximize nutrition because the body can become depleted of certain nutrients. Moreover, it may be necessary to avoid certain foods that can trigger symptoms. For instance, lactose intolerance is quite common among individuals suffering from Crohn’s disease. For this reason, it is generally advised to restrict the consumption of milk, yogurt, cheeses or other dairy products.

What is FODMAP?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are carbohydrates that are poorly digested by the human body. When they are digested, they cause commotion within the intestines, in turn producing gas and triggering symptoms such as bloating, pain, and sometimes loose stools or diarrhea. The low FODMAP diet has proven to be effective in alleviating symptoms associated with IBS. Since Crohn’s disease shares some of the same symptoms as IBS, this diet is being considered for its management.

Where did this diet come from?

Monash University in Australia, Department of Gastroenterology, introduced the first low FODMAP diet. The following chart is a list of foods to include (low or no FODMAPs), foods to eat in small amounts, and foods to avoid (high FODMAPs), as recommended by researchers at the University:

Foods to Include (Low-FODMAPs)

Foods to Eat in Small Amounts

Foods to Avoid (High FODMAPs)

Meat and fish

Beef, chicken, eggs, fish, kangaroo, lamb, pork, prawns, salmon, sardines, shrimp, tuna


Alfalfa, bell peppers, bok choy, brussels sprouts, cabbage (common and red), carrots, collard greens, cucumber, eggplant, endive, fennel bulb, fennel leaves, ginger root, green beans, kale, leek leaves, lettuce, okra, onion tops (greens only [scallion greens]), parsnips, unpeeled potato, pumpkin, radishes, spaghetti squash, spinach (baby), squash, swiss chard, tomato (canned, fresh), zucchini

Broccoli, butternut squash, celery, butternut squash

Artichokes, asparagus, beets, cabbage (savoy), cassava, cauliflower, corn, garlic, leeks, mushrooms, onion (Spanish, white, bulbs) shallots, sugar or snap peas, peas,


Common banana, blueberry, breadfruit, cantaloupe, carambola, clementine, dragon fruit, durian, grapes, kiwi, lemon, lime, mandarin, melon (honeydew), orange, passion fruit, papaya, pineapple, raspberry, rhubarb, starfruit, strawberry, tamarind

Most dried or processed fruits, apples, apricots, avocado, blackberry, boysenberry, cherries, figs, grapefruit, mango, nectarine, peaches, pear, persimmon, plum, pomegranate, watermelon


Oat bran, rice bran, buckwheat groats, maize, millet, quinoa, polenta, quinoa, rice, teff

Buckwheat kernels

Barley, bulgur, wheat bran, couscous, freekeh, spelt, wheat,

Nuts and Seeds

Chestnuts, macadamia, mixed nuts, brazil nuts, peanuts, peanut butter, pecans, pine nuts, walnuts chia seeds, poppy seeds, pumpkin seeds, sesame seeds, sunflower seeds


Almonds, cashews, pistachios

Fats and oils

Butter, margarine, mayonnaise, avocado, canola, olive, peanut, sesame, sunflower and vegetable oils


Cheeses: camembert, cheddar, Colby, cottage, feta, goat, Havarti, mozzarella, pecorino, brie, swiss; whipped cream, lactose free milk, lactose free yogurt, almond milk, hemp milk, soy (protein) milk, coconut milk (from a can)

Cottage cheese, Haloumi, ricotta, sour cream, heavy cream, vanilla ice cream

Buttermilk, custard, kefir, milk, yogurt, oat milk, rice milk, soy (bean) milk, coconut milk (long-life), soya milk

Confections, Sugars, and Sweeteners

Dark chocolate, sugar (brown, white, raw, palm), stevia, maple syrup, rice malt syrup, jaggery

Coconut treacle, white chocolate, milk chocolate

Fruit bar, honey


Fish sauce, BBQ sauce (unless contains onions and garlic), miso paste, oyster sauce, shrimp paste, soy sauce, sweet and sour sauce, tamarind paste, tomato sauce, rice wine vinegar, Worcestershire sauce, mustard, chutney, wasabi, capers in vinegar,

Pesto sauce, quince paste, balsamic vinegar

Ketchup, pasta sauces, relish

Herbs and Spices

Almost all herbs and most spices are allowed

A low FODMAP diet should be maintained under the supervision of a registered dietician. While it is not capable of bringing about or sustaining remission in individuals suffering from Crohn’s disease or ulcerative colitis, it can potentially help manage symptoms and improve quality of life. For instance, during a flare-up, it is only natural to limit foods that could act as triggers. So, if an individual experiences severe diarrhea, it does not make sense to replace loss of fluids with beverages high in FODMAP, such as milk or fruit juice.

What’s the timeline involved?

The general idea behind the FODMAP diet is to avoid or reduce the consumption of foods high in FODMAP for around 3-8 weeks (known as the elimination phase), in an attempt to assess which foods are not tolerated by the body. After the 3-8 weeks, small amounts can be reintroduced to reach a level that will be well-tolerated by the individual. For instance, fructose can be reintroduced the first week and if it does not trigger any symptoms, lactose can be reintroduced as well and so on.

Studying this diet’s effect on IBD

An initial study, conducted in London, involved the participation of patients with IBD who were in remission but had symptoms of IBS. It was found that the patients had all experienced improvements in their symptoms after following a low FODMAP diet. However, instead of testing this analysis further, the researchers aimed to determine whether high doses of FODMAPs aggravated their symptoms. Each patient received a three-day plan, including three various types of FODMAPS. It was found that one type of FODMAP in particular, known as fructans, was associated with more severe symptoms, including stomach pain, bloating, gas, and urgency. As a result, the researchers concluded that eliminating FODMAPS in patients with IBD could prove effective in alleviating symptoms and improving quality of life.

Another study, conducted in Denmark, involved the participation of patients with IBD who were in remission but had symptoms of IBS. The patients were divided into two groups randomly and one group was instructed to follow a low FODMAP diet for a period of six weeks. During this time, their symptoms were monitored. The researchers conducting the study found that the patients following the low FODMAP diet were more likely to experience a significant decrease in their IBS-like symptoms (81%), in comparison to those following their normal diet (46%). What’s more, the patients undergoing the low FODMAP diet were found to experience overall quality of life improvements. While the study had its limitations, the findings were definitely encouraging.


To date, evidence shows that a low FODMAP diet can help alleviate symptoms associated with irritable bowel syndrome (IBS). However, to separate fact from fiction, there is no evidence to suggest that it will work for individuals with inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis. Still, some individuals have found that the diet is helpful in managing some of their symptoms. While the low FODMAP diet is gaining popularity, it does not necessarily mean that it is a safe or appropriate diet for every single individual. It is important to note that following a low FODMAP diet is not meant to be a permanent solution, as it can result in nutritional deficiencies. It is merely a specific diet recommended for a short period of time, in order to give the gastrointestinal tract a chance to alter any imbalances and heal.