HealthInfo Canterbury
Low-FODMAP diet
FODMAPs are a group of carbohydrates (sugars) that some people don't absorb well. If you don't absorb these sugars well, they pass into your large bowel where they provide food for the bacteria that normally live there. The bacteria break down (ferment) these sugars to produce gas, which can cause bloating, pain, and other IBS symptoms.
Many of the foods we eat contain FODMAPs. FODMAP stands for:
- Fermentable – foods that bacteria in the gut can break down quickly
- Oligosaccharides – fructans and galacto-oligosaccharides (GOS)
- Disaccharides – lactose
- Monosaccharides – fructose
And
- Polyols – sorbitol, mannitol and xylitol.
The low-FODMAP diet is a short-term eating plan where you avoid foods that are high in FODMAPs to see if your symptoms improve. Following a low-FODMAP diet improves symptoms for three out of four people with IBS.
Before you try a low-FODMAP diet, it's best to see a dietitian. A dietitian will look at how you eat, identify what foods trigger your symptoms and make sure you're getting all the nutrients you need to stay healthy.
Your GP may refer you for group education on the low-FODMAP diet if you're eligible.
You can get more information about the low-FODMAP diet approach for IBS through the following links:
- Common foods containing FODMAPs – This one-page information sheet from the Healthy Food Guide provides a list of some of the common foods that contain FODMAPs and a list of suitable foods to include on a low-FODMAP diet. The lists aren't complete. A dietitian can give you a full, up-to-date list during a consultation.
- Monash University has a lot of information and frequently asked questions about the low-FODMAP diet including a sample meal plan. It has created a Low FODMAP diet app (you have to pay for this). It has also created the three-minute video that's at the top of this page. The video explains how FODMAPs can trigger IBS symptoms.
The low-FODMAP diet is not a lifetime diet
Don't stay on the low-FODMAP diet for more than six weeks. If your symptoms go away or get much better, you'll know that one or more FODMAPs are an issue. You can then gradually reintroduce one FODMAP group at a time to find out which ones cause your symptoms and how much of each you can tolerate. It's best to do this with the guidance of a dietitian.
Many people who are FODMAP-intolerant can return to their normal diet, just needing to avoid high amounts of a few high-FODMAP foods. Monash University gives a good explanation on why you shouldn't stay on the low-FODMAP diet for life.
If your IBS symptoms don't go away or get better after four weeks, then you don't have a problem with FODMAPs. You should go back to eating normally and talk to your GP or practice nurse.
Written by HealthInfo clinical advisers. Last reviewed July 2021.
SourcesReview key: HIIBS-27995
