What Is the Low FODMAP Diet?

By Kristi King, MPH, RDN, CNSC, LD
Woman with open refrigerator - What Is the Low FODMAP Diet?

cyano66/iStock/Thinkstock

Recently discussed in the popular press, the low FODMAP Diet has generated quite a buzz lately. This eating plan was originally developed to help manage the symptoms associated with irritable bowel syndrome. But wait, what exactly is a FODMAP? Should you be following this diet?

What Is a FODMAP?

FODMAP is an acronym for:

Fermentable
Oligosaccharides
Disaccharides
Monosaccharides
and
Polyols

These short-chain carbohydrates are found naturally in many of the foods we eat. These particular types of carbohydrates share three important characteristics: they are poorly absorbed in the intestine, draw extra water into the intestine and are rapidly fermented by bacteria in the bowel. Depending on the quantity consumed and an individual's tolerance, FODMAPs can lead to increased gassiness, bloating, abdominal pain and diarrhea. 

Prior to starting any new diet, consult a medical professional to rule out celiac disease, cancer and food allergies or intolerances. If a FODMAP diet is prescribed, working with a registered dietitian nutritionist is especially important.

Four Types of FODMAPs

  • Oligosaccharides
    There are two different groups of oligosaccharides: fructans and galactans. Fructans are found in wheat products, onions, garlic, artichokes and inulin. Galactans are found in lentils, chickpeas, broccoli, beans, Brussels sprouts and soy-based products.
  • Disaccharides
    The most commonly known disaccharide is lactose, which naturally occurs in milk and some dairy products and requires lactase, a digestive enzyme, for absorption. Milk, yogurt, soft cheeses, ice cream and puddings are all disaccharides containing lactose.
  • Monosaccharides
    Fructose is a monosaccharide found in fruits. Fructose absorption is enhanced when it is combined with sources of glucose, another type of sugar. Therefore, when it comes to FODMAPs, not all fruits are equal. Those containing equal amounts of fructose and glucose may be more easily tolerated. Some examples of higher-fructose containing foods that may cause gastrointestinal symptoms include (but is not limited to) agave, honey, mangos, watermelon, sugar snap peas and high fructose corn syrup.
  • Polyols
    Polyols are sugar alcohols found in some stone fruits (such as cherries and nectarines), apples and pears; in vegetables such as mushrooms and cauliflower; and in some sugar substitutes containing xylitol or sorbitol. 
How the Low FODMAP Diet May Work

This diet starts with a low FODMAP period, usually ranging from six to eight weeks. Then, under a medical professional's observation, a patient will gradually reintroduce certain FODMAP containing foods. During the reintroduction period, it is vital to keep track of signs and symptoms of gastrointestinal distress in order to help identify food offenders.

Reintroduction is important because over-restriction can cause harm too. Cutting too many fruits, vegetables, plant-based proteins and dairy foods from the diet can lead to increased risk of deficiencies in nutrients such as fiber, minerals such as calcium, protein (for vegetarians or vegans) and vitamins A, C and D. A registered dietitian nutritionist can help manage the reintroduction phase by developing an eating plan that meets an individual's nutrient needs. Remember, this is a low FODMAP diet, not a no FODMAP diet; it is a highly individualized therapy that was designed to help manage symptoms, not to cure them completely.

Find an Expert

Need serious help making a plan? The nutrition experts in our professional membership are ready to help you create the change to improve your life.

Search Now