Health Tips > Nutrition Bites > What is a Low FODMAP Diet?

What is a Low FODMAP Diet?

View All Section Pages


According to the International Foundation for Gastrointestinal Disorders, irritable bowel syndrome (IBS) affects around 25-45 million people in the United States. IBS causes altered bowel habits such as chronic diarrhea, constipation or both, in addition to abdominal pain and discomfort. IBS affects more women than men and can only be diagnosed by a medical professional. 

The low FODMAP diet is a therapeutic approach to help manage symptoms experienced with IBS. FODMAP stands for:




Monosaccharides and


FODMAPs are found in common foods and are consumed daily by most people without causing adverse symptoms. 

How FODMAP is used to manage IBS symptoms

The low FODMAP diet is an elimination diet used to identify specific food groups that worsen symptoms experienced with IBS. High FODMAP foods are made up of short chain carbohydrates which are poorly absorbed in the small intestine and attract more water as they travel from the small intestine to the colon. Once in the colon, the non-digested carbohydrates are fermented by bacteria, causing an increase in production of gas. As a result, the increased content in the intestines causes stretching of the intestinal wall, activating the nerves in the gut.

Individuals with IBS experience intensified sensations in the gut and feel pain, bloating symptoms or altered bowel habits greater than individuals without IBS. The low FODMAP diet is effective in reducing gastrointestinal symptoms in 60-80% of individuals who suffer from irritable bowel syndrome according to Monash University studies. 

The Three Phases of FODMAP

The low FODMAP diet consists of three phases—elimination, reintroduction and personalization. This three-phase approach works to eliminate foods that worsen IBS symptoms. 

  • Phase 1 - The initial elimination phase consists of a 4–6-week washout period where high FODMAP foods are limited. Examples of high FODMAP foods include milk, wheat, garlic, onion, apples, peaches, honey, cashews and pistachios.
  • Phase 2 - After a 4–6-week washout period, if IBS symptoms have improved, the reintroduction phase is initiated. During the reintroduction phase high FODMAP foods are reintroduced one at a time and tolerance is evaluated. This phase typically lasts 6-8 weeks to allow for each FODMAP subgroup to be reintroduced individually. 
  • Phase 3 - Personalization of the long-term diet. This phase allows for a more liberalized diet to be consumed while only reducing FODMAP subgroups that were poorly tolerated during the reintroduction phase. The personalization phase is important to allow for more flexibility, quality of life and a more varied intake of foods to include adequate fiber, vitamin and mineral intake for long-term health. 

The FODMAP elimination diet should be initiated under the supervision of a registered dietitian nutritionist. Cooper Clinic registered dietitian nutritionists can help you navigate the three-phase diet, provide guidance when dining out and ensure adequate nutrient and prebiotic intake during the elimination periods. 

To schedule a one-on-one consultation with a Cooper Clinic registered dietitian nutritionist who specializes in digestive health or learn about Cooper Clinic Nutrition’s services, visit or call 972.560.2655.

Article provided by Kirstin Taylor, MS, RDN, LD, and Cooper Clinic Nutrition.