2. What are FODMAPs & how do they trigger IBS symptoms?

The low FODMAP diet is a type of dietary therapy that can improve IBS symptoms. In this lesson we’ll look at what FODMAPs are, and how they trigger IBS symptoms.

By Laura Tilt

What are FODMAPs?   

FODMAPs are a group of short-chain carbohydrates found in various foods. These include starchy foods like bread, some fruits and vegetables and some types of dairy foods.   

The word FODMAP stands for:  

  • Fermentable (meaning that bacteria can break them down)  
  • Oligosaccharides 
  • Disaccharides  
  • Monosaccharides 
  • And 
  • Polyols   

*Oligosaccharides, Disaccharides, Monosaccharides and Polyols are scientific names for different carbohydrates. These names describe how many sugars each group make up each group, but you don't need to remember them. The term 'FODMAP' is an easy way to remember them as a whole.  

How do FODMAPs cause symptoms?  

When we eat carbohydrates, the gut breaks them down into individual sugars. Usually, these sugars get absorbed in through the small intestine and into the bloodstream, providing us with energy. 

 Unlike other types of carbohydrates, FODMAPs aren’t well absorbed during digestion. This means that they travel though the small intestine to the large intestine.  

 When they arrive in the large intestine, bacteria that live there break them down. This is fermentation. When carbohydrates are fermented, gases are released. These gases can stretch the walls of the gut, triggering tummy pain, gas and bloating in people with IBS.  

FODMAPs can also attract water into the gut during digestion, causing diarrhoea.  

Where did the low FODMAP diet come from?  

The low FODMAP diet was developed by a group of gut health researchers working at Monash University in Melbourne Australia.    

They found that some carbohydrates were not well absorbed in the small intestine. They called these groups of sugars ‘fermentable carbohydrates’ or FODMAPs.    

Their research went on to show that FODMAPs were capable of triggering symptoms like gas, bloating and loose stools in people with IBS.   

They also found that reducing FODMAPs could improve symptoms and help people manage their IBS better.   

Will the low FODMAP diet work for me?  

Research shows that up to 75 % of people with IBS feel an improvement in their symptoms with a low FODMAP diet.  

There’s currently no way of predicting if you'll feel better on a low FODMAP diet without trialling it. The only way to know if you are sensitive to FODMAPs is to follow a low FODMAP diet for 2-6 weeks. This is what we'll be supporting you with through this programme.

If your symptoms improve during this time, it's likely that FODMAPs are a trigger for you.  

If you don't have any improvement in your symptoms when following a low FODMAP diet, it's unlikely they are a trigger for you. If this happens, you can then explore other therapies.  We'll share more about these in later lessons.