Research in recent years has shown that many people with irritable bowel syndrom (IBS) are intolerant to certain naturally occurring sugars, called FODMAPs. People with IBS absorb these sugars poorly, they then then pass rapidly into the large gut where they act as ‘fast food’ for all the bacteria that live there.

The bacteria ferment the sugars, produce gas and cause many of the classic symptoms of IBS such as bloating, abdominal pains and loose stools.

Over the last few years, research has demonstrated that moving to a diet which is low in these  FODMAPS can be very effective.


The research base is convincing, and research from Monash University in Melbourne shows that 86% of people have good resolution of their symptoms by moving to a low FODMAP diet. This discovery has fundamentally changed the way we manage IBS, and a low FODMAP diet is now part of new NICE 2015 guidelines for IBS

At first, the low FODMAP diet seems complicated and restrictive. However, you soon get used to it and the results can be so effective that most people are then very happy to continue with it. It is about avoiding foods which are high in FODMAPS, and replacing them with alternatives which are not. Importantly the diet is:

  • lactose free, so you have to buy lactose free dairy products
  • gluten free, replace wheat flour and gluten with gluten free products made from corn, oats and rice
  • you have to replace some fruit and veg which are high in FODMAPS (e.g. apples, pears, mushrooms, onions etc) with others which are low in them (e.g. grapes, bananas, green beans, carrots etc)

There are a number of books about the diet, we would recommend The Low FODMAP diet as it has been written by two of the key researchers in the field. The book explains in detail about the diet, but also contains lots of great looking recipes. If you have a smart phone there is also a phone app which has also been developed by the research team. It is quick and easy to use and instantly tells you whether a food is high or low in FODMAPs.

Our advice for IBS is to first try simple dietary changes, for example following the British Dietetic Association IBS and Diet fact sheet or NICE initial IBS and Diet Advice. If after a month or two of these simple changes your symptoms persist, to then try a low FODMAP diet. If your symptoms still persist, then return to see your doctor. In difficult cases referral to a dietician may be helpful. Switching to a low FODMAP diet takes time and commitment, but the good news is that for most people with IBS good control of your symptoms without needing drugs or medication is now an achievable goal.

For more details on IBS and diet see: