FODMAPs are carbohydrates that contain short chains of sugars or sugar alcohols that are poorly absorbed in the gut and are fermented by microbes in the colon. FODMAPs include lactose (glucose and galactose), fructose (when in excess of glucose), fructans, galacto-oligosaccharides (GOS), and polyols, (e.g. sorbitol and mannitol).

FODMAP is an acronym that stands for:

  • Fermentable - fermented or digested by bacteria in the large intestine.
  • Oligosaccharides - “oligo” means few and “saccharide” means sugar. These molecules are made up of individual sugars joined together in a chain.
  • Disaccharides - “di” means two. Two sugars bound together.
  • Monosaccharides - “mono” means single. This is a single sugar.
  • And
  • Polyols - these are sugar alcohols (although they have alcohol in the name, they do not contain alcohol).

A diet low in FODMAPs (Low FODMAP Diet) has been proven to be a very effective dietary method for decreasing symptoms of IBS (Irritable Bowel Syndrome). Symptoms of IBS, which may improve with a low FODMAP diet, include gas, abdominal pain, bloating and distension, nausea and changes in bowel habits (diarrhea and/or constipation).

How do FODMAPs trigger symptoms of IBS?

FODMAPs may be poorly digested and therefore will be poorly absorbed in the small intestine and when they enter the large intestine, two major events may happen:

  • Bacteria in the large intestine readily ferment the FODMAPs, contributing to the production of gas.
  • The FODMAPs are also highly osmotic, meaning that they attract water into the large intestine, which can alter how quickly the bowels move.

These two processes can then trigger symptoms including excess gas, abdominal bloating and distension, abdominal pain, constipation or diarrhea, or a combination of both.

People may have a response from some FODMAPs but not all. However, it is difficult to determine which foods are provoking symptoms without eliminating them all. By eliminating foods that contain FODMAPs, individuals can significantly reduce or even eliminate their IBS-type symptoms.

The Low FODMAP Diet is proven to be an effective dietary treatment for people suffering from IBS. Consuming foods that are “FODMAP Friendly” complies with the Low FODMAP Diet.


Shepherd SJ, Parker FJ, Muir JG, and Gibson, PR Dietary triggers of abdominal symptoms in patients with irritable bowel syndrome-randomized placebo-controlled evidence. Clin. Gastroenterol. Hepatol. 2008; 6(7): 765-771
Halmos, EP, Power VA, Shepherd SJ, et al. A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome_ Gastroenterology 2014: 146(1) 67-75
Ong DK, Mitchell SB, Barrett JS, Shepherd SJ, Irving PI, et al. Manipulation of dietary short chain carbohydrates alters the pattern of hydrogen and ethane gas production and genesis of symptoms in patients with irritable bowel syndrome. J Gastroenterol. Hepatol. 2010 Aug; 25*8): 1366-73
Barrett JS, Irving Pm, Gearry R, Shepherd SJ, Gibson PR Comparison of the prevalence of fructose and lactose malabsorption across chronic intestinal disorders Aliment. Pharmacol. Therapeutics 2009; 30(2): 165-74