First things first. The low FODMAP diet is not a ‘diet’ in the normal sense of the word. It isn’t about losing weight and it certainly isn’t about cutting out a particular food group. It is a way of eating that helps many people to reduce the symptoms of food induced IBS (Irritable Bowel Syndrome).

It was developed by a team at Monash University in Melbourne, Australia. In 2005, researchers in the university’s Department of Gastroenterology identified a group of short-chain carbohydrates (sugars) which are present in food and which are either not completely digested, or are poorly absorbed in the small intestine, where they move sluggishly and draw water into the bowel. They consist of Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols which is a bit of a mouthful, even for scientists, so the research team helpfully came up with the acronym ‘FODMAPs’.

As FODMAPs pass into the large intestine, they are fermented by gut bacteria and produce gas. It’s a perfectly normal process which causes no problems for most people, but those who suffer from IBS have a much more sensitive gut and the gas and water can cause great pain and discomfort.

FODMAPs occur naturally in a wide range of ordinary foods including certain types of grains and cereals, some fruits and vegetables and dairy products but the amount and type of FODMAP varies hugely between different foods. Since identifying them, the team at Monash University have gone on to test hundreds of different foods to identify the type and amount of FODMAPs in each one and from this ongoing research, they have developed the low FODMAP diet.

The FODMAP groups

Oligosaccharides include Fructans and Galactooligosaccharides (GOS) and are found in foods including onions, garlic, wheat legumes and pulses and certain vegetables

Disaccharides are in lactose and occur in dairy products such as milk

Monosaccharides are in fructose and are found in fruits such as apples and mango and high fructose foods such as honey

Polyols are in Sorbitol and Mannitol and occur in some fruits, especially stone fruits, and vegetables including cauliflower and mushrooms and are also often used in artificial sweeteners

How the low FODMAP diet works

The low FODMAP diet follows three stages and Monash recommends that it is followed with the help of a registered dietitian who is trained in the low FODMAP diet. Monash has also developed a superb app which helps users to check food items and determine their FODMAP content.

The first stage of the low FODMAP diet is elimination, when all potential high FODMAP food triggers are eliminated from the diet. This is also known as ‘eating green’ because in the Monash app, green is the colour given to foods that are low in FODMAPs or to foods which can be served in a portion size which is low FODMAP. This way of eating is maintained for a few weeks, until IBS symptoms are under control.

The next stage is re-introduction, whereby foods from each of the categories are added into the diet in measured portion sizes and symptoms are monitored to see if they have an adverse affect and at what portion size.

Once ‘trigger foods’ have been identified, the aim is to start eating as normally as possible whilst avoiding the trigger foods so that IBS symptoms are kept under control or manageable. Many people find they are intolerant to just one of two of the FODMAP groups rather than all of them, so there is no need to avoid all FODMAPs in the future, just the ones known to cause symptoms. Monash also recommends trying to re-introduce known triggers from time to time, as tolerances can change after a while.

The causes of IBS are still little understood, but it is likely that many things affect symptoms, including stress and hormones, so sometimes it isn’t a foodstuff that will bring on symptoms. However, the low FODMAP diet has been scientifically tested and proven to help three out of four people who suffer with IBS, so it is a valuable way of trying to control symptoms and has literally been life-changing for some.