What are FODMAPs?

FODMAPs are…

FODMAPs are a group fermentable carbohydrates that are poorly absorbed in the small intestine of humans.

The term “FODMAP” is an acronym:

Fermentable – fermentation is a metabolic process that turns carbohydrates into acids, gases and alcohols.

Oligosaccharides – FOS and galactooligosaccharides (GOS/galactans); indigestible fibres.

Disaccharides – di = two, saccharide = sugar; a sugar molecule comprised of two monosaccharides, lactose (glucose-galactose).

Monosaccharides – mono = one; single sugar units, such as fructose, glucose (which isn’t a FODMAP, even though it is a monosaccharide) and galactose.


Polyols – sugar alcohols that occur naturally in fruits or are man made, they are often added to “sugar free” products, as they are not calorie dense. Examples include sorbitol, maltitol, erythritol and xylitol.

The key thing here is that they are FERMENTABLE. If you are one of the approximately 30% of people who malabsorb certain carbohydrates, the FODMAPs you ingest will progress further down your digestive tract than they should and enter your colon, where the resident gut flora will digest (ferment) them.

This leads to the production of hydrogen, methane and carbon dioxide gases and short chain fatty acids, which will also have an osmotic effect on your large intestine and increase its water content.  Simply put, excess FODMAP ingestion in those prone to carbohydrate malabsorption could lead to gas, bloating, abdominal cramps/pain and altered bowel movements – the hallmarks of IBS and symptomatic fructose malabsorption.

If you have issues with fructose and fructans, you do not automatically need to avoid all the different FODMAPs long-term; many can be tested for individually or ruled out with an elimination diet and food trial period. However, if you are still symptomatic on a fructose friendly diet, the other FODMAPs might be worth investigating.

Which conditions are linked to FODMAP malabsorption?





  • Fructose malabsorption (sorbitol further reduces the absorption of fructose, regardless of whether it is itself malabsorbed).
  • Irritable bowel syndrome.
  • Mannitol malabsorption.
  • SIBO.
  • Sorbitol malabsorption.