FODMAP diet, what for? For whom?

If you don’t know what the FODMAP diet is, I first recommend you to start reading this article.

Do you know what this diet is all about?

Perfect, let’s see how the FODMAP diet has been developed and whether it can benefit you.


The context

For a long time, patients with gastrointestinal disorders recognized that certain foods could trigger and/or worsen their symptoms (gas, diarrhea, abdominal bloating, and discomfort).

The main “culprits” were (and still are): milk and other dairy products, legumes, cruciferous vegetables, some fruits and cereals, especially wheat and rye.

Physicians and dietitians have advised patients complaining of excessive bloating and gas to avoid these “gas-producing foods” for a long time, but without having a specific protocol and without scientifically evidences.

Thanks to scientific and technological advances, the components of these foods, which first appear to be unrelated, have been linked.

Also, the malabsorption of carbohydrates has been recognized as causing diarrhea, pain and bloating. This malabsorption and was subsequently involved as a cause of symptoms of irritable bowel syndrome (IBS).


  • Lactose

Lactose is milk sugar. In order to be digested and absorbed, an enzyme, called lactase, is needed.

Congenital (innate) lactase deficiency was first reported in 1959. Lactose intolerance due to an adult lactase deficiency was not described until 6 years later.

It’s easy to know if you’re lactose intolerant. A simple breath test measuring exhaled hydrogen (gas) levels following the ingestion of a lactose drink gives clear and accurate results.

Lactose-free diets have become a dietary strategy for IBS patients, but unfortunately have not had a major impact on symptoms overall.

In my practice I often notice that patients already “know” that they are lactose intolerant and have stopped eating dairy. Howeverbeing lactose intolerant does not mean that it is necessary to deprive yourself of all dairy products. Of course, dairy products are not essential and are pro-inflammatory in the majority of cases, but even if you have a lactase deficiency you can consume it up to a certain threshold (called a tolerance threshold).



I self-declared lactose intolerant. If I drink glass of milk I can assure you that within an hour I will need toilets! Still, I can eat yoghurt or cheese without having any symptoms. You can do the breath test if you want to have a diagnosis, but often observing the reactions of our body is enough.


  • Fructose and sorbitol

Fructose, the major sugar in fruit, was convicted following an experiment in 4 patients. These patients have seen their symptoms (chronic diarrhea and colitis) disappear as a result of a fructose-free diet.

In 1988, it was observed that many children developed digestive problems as a result of ingestion of fruit juices. The term “fruit-juice diarrhea” was born. (1)

Fructose malabsorption is becoming increasingly recognized.



Caution! The absorption of fructose depends on glucose (another simple sugar). We are not all equal and tolerated doses of excess fructose compared to glucose vary from person to person. Fructose malabsorption is not an enzymatic deficit problem. It will express itself more or less strongly depending on the total composition of the meal.


  • Oligosaccharides

The symptomatic response to fructo-oligosaccharides that were used as a sweetener was reported in 1987. Multiple studies followed.

Galacto-oligossacharide (GOS) began to be used as prebiotics in 1990. As a result, people have reported having gastrointestinal symptoms. GOS were therefore blamed as symptom-inducers. (1)


  • Fructans

In 2006, the restriction of fructose and fructans in a well-structured and defined diet specifically for patients with IBS and fructose malabsorption gave relief for intestinal symptoms in 76% of patients (1).


  • Polyols

Polyols are alcohol sugars such as mannitol and xylitol. They have long been used as sweeteners in food production, and are still used today. It was in the 1960s that their ability to induce intestinal symptoms was well documented in Turku sugar studies (2).

Additive effects with fructose and sorbitol on symptoms were first reported in 1982. (1)


Linking data

All of these observations, sometimes supported by scientific studies, led the researchers to hypothesize that the improvement of symptoms permitted by the removal of these sugars would be linked to a physiological effect (distension of the intestinal lumen by the production of water and/or gas).

All short chain carbohydrates that are slowly absorbed or indigestible in the small intestine have been included as they have all had similar physiological effects.

In addition, there is a strong “cocktail” effect, meaning when these sugars-type are ingested at the same time, symptoms are even stronger. A restriction of all these sugars allows a clear improvement in symptoms in patients with visceral hypersensitivity.



Acronym origin

The creation of an acronym to describe these short chain carbohydrates was necessary. Firstly, because there was no collective term that included them, but also because at the time, only fructose was often the only sugar considered. (1)

It was in this context that in 2004, Monash University researchers, including Dr. Sue Shepherd and Dr. Gisbon, agreed on the term fermentable Oligosaccharides, Disaccharides and Monosaccharides and Polyols (FODMAP). But it gives a name was only the beginning. It was still necessary for this term to be approved by the scientific community and the general public!

It is thanks to a study published in Alimentary Pharmacology and Therapeutics, hypothesizing that the FODMAP diet would be appropriate for Crohn’s disease, that the term FODMAPs has been extended worldwide. (3)

Since then, numerous studies aimed at more precisely determining the mode of action of FODMAPs,but also in the analysis of foods and the development of thresholds that define a portion poor in FODMAPs, the creation of tools for assessment, identification of potential risks,and contexts of applications have been conducted.

An app to help people with IBS or others using the FODMAP diet to improve their condition was developed largely by Jane Muir.







For whom?

It is estimated that 70-80% of people with irritable bowel syndrome (also known as irritable bowel or functional colopathy), have their symptoms diminished or disappear as a result of FODMAPs eviction.

It is in this context that the FODMAP diet is mostly indicated.


The FODMAP diet can also be recommended for various pathologies.


  • Celiac disease

It is important to remember that the total exclusion of gluten for life is the only treatment for celiac disease. However, even if you follow a gluten-free diet, it is possible to still experience digestive symptoms. In this case, following a FODMAP diet may relieve and highlight poorly tolerated foods which trigger symptoms.

Although gluten-free foods and preparations are (usually) wheat-free, not all are low in FODMAPs.

If this is your case, be sure to seek the advice of a dietician. This will 1) ensure that there are no traces of gluten in your diet 2) determine whether the FODMAPs-poor diet is appropriate 3) to choose the right supplements necessary for your intestinal and overall health.


  • Chronic inflammatory bowel disease MICI

In the flare-up phase, patient with Crohn’s disease or hemorrhagic colitis are advised to adopt a diet that is low in fibre and/or high in protein and energy.

If you have IBD and you are reviewing the dietary and behavioural advice given by your doctor or dietician, but you arestill experiencing many digestive disorders, then the FODMAP diet may help.

According to Dr. Shepherd, people with IBD are more affected by lactose malabsorption and/or are less tolerant of excess fructose than the average. (4)


  • Functional dyspepsia

In case of constipation or chronic diarrhea which are not linked with IBS (they are functional), the FODMAP diet can help.


  • In paediatrics

The FODMAP diet may be recommended for some children in a specific context. Follow-up by a health professional is essential because the risks of nutritional deficiencies are higher.




What to remember?

The FODMAP diet is relatively new but more and more resources become available.

This diet can be prescribed following the diagnosis of IBS or other diseases inducing gastrointestinal symptoms (SIBO, candidiasis, MICI…). It is usually not enough on its own. Simultaneously, a change in lifestyle as well as an intestinal regeneration are often necessary.

Given its complexity and the risks it can entail, it is strongly advised to be followed by a specialized health professional.



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(1) Peter R Gibson (February 28, 2017). History of the low FODMAP diet. Journal of gastroenterology and hepatology. Available:

(2) Scheinin A, KK. Turku sugar studies. An overview. Odontol Acta. Scand. 1976; 34 (6): 405– 408.

(3) Gibson PR, Shepherd SJ. Personal view: food for thought-western lifestyle and susceptibility to Crohn’s disease. The FODMAP hypothesis. Food. Mr. Pharmacol. Mr. Ther. 2005; 21: 1399– 1409

(4) Food intolerance management plan, additional information from the book:

Images from the training offered by Monash University dedicated to health professionals.




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