What is a FODMAP diet and how does it help IBS?

Understanding IBS

Irritable Bowel Syndrome (IBS) is a common digestive condition affecting the stomach and intestines. Symptoms can include stomach cramps, bloating, diarrhoea and constipation, which may come and go over time. While IBS has no cure, lifestyle and dietary changes are often recommended to help manage it (1).

What Are FODMAPs?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. These are types of carbohydrates (sugars) that some people find hard to digest. When poorly absorbed, they can ferment in the gut, producing gas and drawing water into the bowel, which may trigger IBS symptoms such as bloating, wind and pain (2).

The Low-FODMAP Diet Explained

The low-FODMAP diet is a structured approach designed to help identify whether certain high-FODMAP foods are contributing to IBS symptoms (2,3). It has three main stages:

-       Elimination phase – High-FODMAP foods are temporarily avoided for a few weeks.

-       Reintroduction phase – Foods are gradually reintroduced one by one to see which cause symptoms.

-       Personalisation phase – A long-term eating plan is developed that avoids only the problematic foods while including those that are well tolerated.

This method is not a lifelong diet. Instead, it helps people discover which foods affect them, so they can manage symptoms while keeping their diet varied and balanced (2).

Why It May Help in IBS

Research has shown that reducing high-FODMAP foods may relieve common IBS symptoms such as bloating, abdominal pain and diarrhoea. According to the Cleveland Clinic, up to 70% of people with IBS report symptom improvement on a low-FODMAP diet (2).

In the UK, the NHS recommends seeking advice from a healthcare professional if symptoms persist after trying first-line diet and lifestyle changes. In some cases, patients may be referred to a dietitian to try a low-FODMAP plan (1).

Important Considerations

The low-FODMAP diet should ideally be followed with the support of a registered dietitian.

It is not suitable for everyone and should only be tried if basic diet and lifestyle measures have not worked.

Because many high-FODMAP foods are also sources of fibre and beneficial nutrients, the elimination phase should be short-term (2,3).

Summary

The low-FODMAP diet is a temporary but structured way to identify food triggers that worsen IBS symptoms. While it isn’t a cure, it can be a valuable tool for people whose symptoms don’t improve with standard dietary changes. Professional guidance is key to ensure the diet is safe, balanced, and effective.

References

1. https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/further-help-and-support/
2. https://my.clevelandclinic.org/health/treatments/22466-low-fodmap-diet
3. https://www.nhsinform.scot/illnesses-and-conditions/stomach-liver-and-gastrointestinal-tract/irritable-bowel-syndrome-ibs/managing-irritable-bowel-syndrome-ibs/