11th May, 20204 min read

What’s the low FODMAP diet?

Medical reviewer:
Healthily's medical team
Healthily's medical team
Tomas Duffin
Tomas Duffin
Last reviewed: 12/05/2020
Medically reviewed

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The low FODMAP diet is an elimination diet that’s generally used to help people with symptoms of irritable bowel syndrome (IBS), such as bloating and constipation.

An elimination diet involves cutting out the foods you suspect are causing your symptoms before slowly reintroducing them to see if your symptoms come back.

Typically, the foods you think are causing your symptoms can be cut from your diet 1 at a time to see what effect, if any, this has. These foods can then be left out of your diet for 2 to 6 weeks, during which time you can see if your symptoms improve.

This type of diet can be effective for managing conditions such as IBS because it helps you identify which foods cause you problems.

So, what is the low FODMAP diet all about?

What does ‘FODMAP’ stand for?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols.

These are a collection of simple and complex sugars found in some fruits and vegetables, milk and wheat that the gut has difficulty breaking down and absorbing.

What does the low FODMAP diet do?

The low FODMAP diet cuts out some or all of these foods to limit the amount of these sugars in your diet.

This reduces the amount of gas produced by gut bacteria while your food is digested and can help to improve the symptoms associated with IBS, including wind, bloating and pain.

What could you eat less of on the low FODMAP diet?

Some foods are considered ‘high FODMAP’, meaning they are difficult to digest and have been known to make symptoms worse for people with IBS.

High FODMAP foods

What could you eat more of on the low FODMAP diet?

Some foods are considered ‘low FODMAP’ foods, meaning they are considered easier to digest for people with IBS.

Low FODMAP foods

Remember that the idea is to limit the foods that are causing you problems, not to eliminate all high FODMAP foods and replace them with low FODMAP alternatives.

Should you see a doctor before trying the low FODMAP diet?

If you have IBS symptoms and are keen to try a low FODMAP diet, you should see a doctor or dietician before you do.

A low FODMAP diet can be difficult to follow, so you may find it helpful to have the guidance of a dietitian who can make sure that you’re still covering each of the major food groups in your meals, which are:

  • fruit and vegetables
  • starchy food
  • protein
  • dairy
  • fat

A dietitian can also provide you with the most up-to-date FODMAP food lists - the lists found online may be incorrect or out of date.

Does the low FODMAP diet actually work?

Reducing high FODMAP foods can improve IBS symptoms for around 3 in 4 people.

However, the low FODMAP diet isn’t easy to follow, and to test how effective it is you may need to cut out a lot of foods before slowly reintroducing them to your diet.

For more guidance on managing IBS symptoms, read about diagnosing and treating IBS.


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Irritable bowel syndrome (IBS) [Internet]. nhs.uk. 2020 [cited 14 January 2020]. Available here.

MBE D. Fibre, the low FODMAP diet and gut bacteria [Internet]. Patient.info. 2020 [cited 14 January 2020]. Available here.

Irritable bowel syndrome - Symptoms, diagnosis and treatment | BMJ Best Practice [Internet]. Bestpractice.bmj.com. 2020 [cited 14 January 2020]. Available here.

Harding D. Irritable Bowel Syndrome. About Irritable Bowel Syndrome (IBS) [Internet]. Patient.info. 2020 [cited 14 January 2020]. Available here.

The five main food groups - Healthy eating |Food Standards Scotland [Internet]. Foodstandards.gov.scot. 2020 [cited 14 January 2020]. Available here.

Food intolerance [Internet]. nhs.uk. 2020 [cited 10 February 2020]. Available here.

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