The different types of FODMAPs

FODMAPs are a group of carbohydrates that can lead to symptoms like pain and bloating in people with IBS. There are five different types of FODMAPs:   

1. Fructans

Fructans are chains of the sugar fructose. They are a trigger for most people with IBS.  

Fructans exist in many foods, including grains like wheat, rye and barley, and some vegetables like onion and garlic.

2. Galacto-oligoaccharides or GOS)

Galacto-oligoaccharides (or GOS for short!) are chains of the sugar galactose. The main sources of GOS are peas beans and lentils and some nuts.   

3. Lactose

You might already know about lactose. It’s a naturally-occuring sugar found in milk, and foods made from milk. The main sources of lactose are milk and yoghurt and some cheeses.   

4. Fructose

Fructose is a single sugar found in many fruits and vegetables, honey and fruit juice.   It's the smallest FODMAP and can trigger symptoms when consumed in large amounts.

 5. Polyols

Polyols are also called sugar alcohols. These are a type of carbohydrate found in some fruits and vegetables including stone fruits (like plums and peaches) and mushrooms. They are also used as sweeteners, so often contained in foods like sugar free mints and gum and protein powers.  

Why do the different types of FODMAPs matter?

Not everyone responds to FODMAPs in the same way.

Some FODMAPs (like fructans) might trigger your symptoms, whereas others (like lactose) may have no effect.   

Research from Monash University has found that that most people with IBS are sensitive to fructans and GOS when they are consumed in large amounts.

Fructose, lactose and polyols are only problematic for some people with IBS.

How do I work out which groups I’m sensitive to?

During the first stage of the FODMAP diet, you’ll remove all the different groups of FODMAPs from your diet to see if your symptoms improve.    

If they do, you'll move onto stage 2, reintroduction. During this stage, you’ll test your tolerance to the different FODMAP groups one by one. This will help you understand which ones trigger your symptoms and which ones you can tolerate.  

As you move through stage 2, you'll learn which foods you will need to avoid longer term, and which you’ll be able to add back to your diet at the end of stage 2.