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FODMAPs explained

Let’s dive into what the detail and explore what a low FODMAP diet is and who it is suitable for as some information can seem very confusing!

What are FODMAPs?

FODMAPs are a collection of short-chain carbohydrates (sugars) that attract water in the small intestine and are not absorbed. They travel into the large intestine and are fermented by our gut bacteria which produces gas in all people. Most individuals can consume high FODMAP foods without any symptoms however this fermentation process can cause excessive bloating, wind, diarrhoea and cramping in people with Irritable Bowel Syndrome (IBS).

FODMAP is an acronym that refers to Fermentable, Oligosaccharides, Disaccharides, Monosaccharides and Polyols. See the breakdown below.

F– Fermentable: Process through which gut bacteria ferment undigested carbohydrate to produce gases.

O– Oligosaccharides e.g. Fructans and Galacto-oligosaccharides (GOS), found in foods such as wheat, rye, onions, garlic and legumes/pulses.

D– Disaccharides e.g. Lactose, found in dairy products like milk, soft cheeses and yogurts.

M– Monosaccharides e.g. Fructose, found in foods such as fruit, honey and high fructose corn syrups.

P– Polyols e.g. Sorbitol, mannitol, maltitol, zylitol and isomalt, found in artificial sweeteners and some fruits / veggies.

Who is low FODMAP diet suitable for?

The low FODMAP diet is incredibly effective for people suffering with digestive upset, IBS or fructose malabsorption.IBS is a common functional gastrointestinal disorder that causes abdominal pain, bloating, wind and altered bowl movements and diagnosed by a gastroenterologist or doctor. Fructose malabsorption is diagnosed using a breath test to test the amount of gas (methane and hydrogen) in the breath after consuming a dose of fructose. A rise in gas levels suggest malabsorption, as the gas wasn’t absorbed in the small intestine and exhaled by the lungs. I was personally diagnosed with many years ago and my partner has fructose malabsorption, so understand people’s pain when they experience horrible symptoms associated with some FODMAPs. I often have an IBS flare up when I consume foods high in FODMAPs, as per the image below.

How does a low FODMAP diet work?

There are 3 phases to a low FODMAP:

1. Elimination Phase: Foods high in FODMAP are eliminated for 2-6 weeks and swapped for low FODMAP alternatives. The FODMAP app by Monash University is a great tool to help determine the size of a low-FODMAP serving of different foods and low fodmap certified foods.

2. Reintroduction Phase: Once symptoms have settled after the Elimination Phase a high FODMAP foods are reintroduced across 8-12 weeks whilst continuing a low FODMAP diet. What people don’t realise if that consuming multiple low FODMAP foods in one serving may lead to a high FODMAP food serving and result in gastrointestinal upset, thus 1 FODMAP group is introduced during the reintroduction phase for 3 days and symptoms are tracked. This is to be repeated for all FODMAP groups. The aim is to work out which FODMAPs are causing the issues,as it is unlikely that ALL FODMAP categories will cause symptoms and the quantity of that FODMAP you can consume without symptoms.

3. Personalisation Phase: If you haven’t reacted to a FODMAP group you can reintroduce these foods into your diet. Reintroduce FODMAPS that you had small reactions to in small quantities and avoid adding in foods that you experienced severe reactions to. Now you can start to work out some good low FODMAP alternatives and how to adjust recipes, so they are suitable!

Monash University have outlined a comparison of high and low FODMAP foods in the table below.

The diet should be followed under the guidance of a nutritionist or health practitioner who specialises in this area to ensure the process doesn’t take longer than necessary and ensure the least amount of foods are restricted as possible. It should be noted that reintroducing FODMAPS is extremely important as a low FODMAP diet it is extremely restrictive in nature and can make it difficult when eating out or in social situation. Some high FODMAP foods are also extremely beneficial for our gut health as they act as prebiotics which feed our good gut bacteria.


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