The Different FODMAP Types for IBS Symptoms

What FODMAPs are and why they're important

FODMAPs are types of carbohydrates found in ordinary foods, and research suggests that they may contribute to symptoms in people who have irritable bowel syndrome (IBS). Eliminating high FODMAP foods from their diet helps many people with IBS feel better and may even have value for treating other conditions.

The acronym FODMAP stands for "fermentable oligosaccharides, disaccharides, monosaccharides, and polyols." These are all types of sugars that are poorly absorbed by the small intestine.

Glass of milk with caution tape in front of it
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The Five FODMAP Types

FODMAP foods are broken down into five categories:

1. Fructans: Fructans are found primarily in wheat, many vegetables (most notably garlic and onions), and the food additives FOS and inulin. Fructans are non-digestible and thus are available to be acted upon by gut bacteria. The fermentation that results offers some health benefits but can contribute to unwanted symptoms in a person who has IBS.

2. Fructose: Fructose is the sugar found in many fruits, honey, and high fructose corn syrup. Fructose malabsorption is only a problem for some IBS patients.

3. GOS: GOS stands for galactooligosaccharides, which are sometimes called galactans. GOS can be found in legumes, including beans, chickpeas, and lentils. Like fructans, GOS are non-digestible and thus have similar effects on the body and in IBS patients.

4. Lactose: Lactose is the main sugar found in milk and other dairy products. Not all people with IBS are lactose intolerant. Foods also vary widely in lactose content, and therefore, some lactose-containing foods are allowed on the low-FODMAP diet.

5. Polyols: Polyols are sugar alcohols with scientific names that typically end in "- ol." They are found naturally in some fruits, such as blackberries, and vegetables, such as cauliflower and mushrooms, and are often used as artificial sweeteners. Two naturally occurring polyols are mannitol and sorbitol, and those added to foods include xylitol, maltitol and isomalt. (Note: Not all things ending in "-ol" are polyols.)

Fructans Wheat
Fructose Most juices
Agave syrup
GOS Beans
Soy products
Oat milk
Lactose Cow/goat milk
Ice cream
Baked goods containing milk
Polyols Avocado
Stone fruits
Sweet potatoes
Artificial sweeteners

People who have IBS are typically not sensitive to every FODMAP type. Therefore, the low-FODMAP diet involves initially eliminating all of these types of FODMAPs, then re-introducing each type one at a time. The re-introduction is done in a careful and systematic way to see if the foods are tolerated or cause symptoms.

The ability to pinpoint which FODMAP types are troublesome allows you to eat as wide a variety of foods as possible. It's best to go through the elimination and challenge phases of the diet under the care of a qualified dietary professional.

The Monash University Low-FODMAP Diet App is an excellent resource for identifying the specific FODMAP content of common foods.

Frequently Asked Questions

How long does a FODMAP elimination diet take to figure out which foods trigger my IBS symptoms?

It can take approximately 6-8 weeks, or even longer, to work through an elimination diet and gauge your reaction to individual foods.

Are there over-the-counter medications for IBS?

Yes, nonprescription medications such as anti-diarrheal medication, laxatives, and probiotics, can be used for symptom relief. Your healthcare provider may also want you to try a low-FODMAP diet.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Whelan K, Martin LD, Staudacher HM, Lomer MCE. The low FODMAP diet in the management of irritable bowel syndrome: an evidence-based review of FODMAP restriction, reintroduction and personalisation in clinical practiceJ Hum Nutr Diet. 2018;31(2):239-255. doi:10.1111/jhn.12530

  2. Bellini M, Tonarelli S, Nagy AG, et al. Low FODMAP diet: Evidence, doubts, and hopesNutrients. 2020;12(1):148. Published 2020 Jan 4. doi:10.3390/nu12010148

  3. The Ohio State University Wexner Medical Center. Should you avoid eating fructans?

  4. Monash University. Enzyme therapy can help reduce symptoms in IBS patients sensitive to galacto-oligosaccharides (GOS).

  5. Xiong L, Wang Y, Gong X, Chen M. Prevalence of lactose intolerance in patients with diarrhea-predominant irritable bowel syndrome: data from a tertiary center in southern ChinaJ Health Popul Nutr. 2017;36(1):38. Published 2017 Nov 21. doi:10.1186/s41043-017-0113-1

  6. Monash University. What are the polyols?

  7. Tuck C, Barrett J. Re-challenging FODMAPs: the low FODMAP diet phase twoJ Gastroenterol Hepatol. 2017;32 Suppl 1:11–15. doi:10.1111/jgh.13687

Additional Reading

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.