top of page

FODMAPs & The Low-FODMAP Diet Explained!

As you’re on this page, I can assume you’ve already realised food is a major trigger of your IBS. A group of researchers from the Monash University, Australia found that in most people with IBS (75%), a particular set of carbohydrates was to blame!

Therefore dramatically cutting down the amounts of these specific carbohydrates in your diet can reduce your symptoms, or relieve them completely. There is hope!

This group is often referred to as “FODMAPs” and unfortunately they are found in a wide range of foods, including wheat, beans, vegetables and fruits. Not ideal for vegans, but it is still possible to eat well and manage your symptoms.


This is the acronym used to describe fermentable oligo-, di-, mono- saccharides and polyols.

The four groups of FODMAPs include:

  1. Oligosaccharides: This includes two types of carbohydrate, which need to be re-challenged separately. 1. Galacto-oligosaccharides (GOS), which are found primarily in lentils and beans. 2. Frutans-oligosaccharides (FOS), which are found in certain fruits, vegetables, grains, legumes, nuts and additives, such as garlic, onion, wheat and broccoli.

  2. Disaccharides: This referred to lactose found in some dairy products. Luckily for vegans, this isn’t an issue.

  3. Monosaccharides: The culprit sugar here is fructose. It’s found in high quanities in some fruits, such as mango pears, dried fruits and sweeteners such as honey (luckily not an issue for vegans) and agave nectar.

  4. Polyols: Sugars found in certain fruits and vegetables including prunes and avocado, as well as some artificial sweeteners.

  • I will make some more videos listing all the things you can have and foods to avoid.


They are short-chain carbohydrates which are poorly absorbed, if at all, in the small intestine. Because they dissolve in water (hydrophilic), but they are stuck within the intestine, water molecules are drawn into the intestine through osmosis. This can lead to the diarrhea of IBS you may be familiar with.

As the FODMAPs move along into the large intestine the gut bacteria get involved. This is when the “F” comes into play, as the bacteria Ferment the carbohydrates producing the gases hydrogen, carbon dioxide and methane. Much like a fizzy fermented beer or sauerkraut. The gas can build up in your large intestine resulting bloating and flatulence. Beautiful.

The combination of excess water and gases expands the volume of the intestines, giving extra oomph to the bloating, abdominal distention and stretching of the intestinal walls. The stretching stimulates the numerous nerves around the gut, giving rise to the pain and discomfort you’ll likely recognize when you’re having a bad flare-up.


Everyone experiences some gas being produced when they eat FODMAPS, but in those with IBS it can be excessive and painful.

You can have varying sensitivities to each type of FODMAP and in different combinations. So you might be fine with avocados and wheat separately, but a couple slices of avo-toast will contain that pernicious combo, which will trigger your IBS.

Some foods contain a lot of certain FODMAPs, while others only traces. And some foods will contain just one single type of FODMAP and others will contain a combination. So learning which foods are safe for you, can give you a lot of options, reassurance and a peaceful gut.


Reducing or even relieve your IBS symptoms. In 75-81% of people, across 30 studies of 1000’s of patients, the low-FODMAP diet improved symptoms, including stomach pain, bloating, reflux, flatulence and bowel urgency, as well as diarrhea and constipation.

A rather depressing study found IBS sufferers, who are typically young to middle age adults, would trade 25% of their remaining life to be symptom free... so the benefits of the diet can be immense.


  • The Elimination Phase

For 2-6 weeks you eat a strictly low-FODMAP diet, taking care to ensure your meals have low levels of the FODMAPs. This is called the Elimination Phase and it only needs to be as long as it takes for your symptoms to subside.

  • The Challenge Phase

Once you are happy your symptom are reduced enough or gone altogether, you can enter the “Re-Challenge phase”. You pick one particular FODMAP to test each week.

First you eat a small portion on day one and if it sits well with you, you eat a medium portion the following day. If the medium portion is also okay, you can have a large portion on the third day. Depending how you feel, you can gauge how well you tolerate the tested FODMAP.

You’ll then take a a few “clear-out” days of purely low-FODMAP foods, before moving on to the next FODMAP to be tested. Think of it as an experiment and by keeping all other factors constant, you can properly test one variable at a time.

In total, vegans will need to re-challenge 9 FODMAPs and non-vegans will have to test 10 (as they eat dairy, boo).

  • The Reintroduction Phase

This is where things start getting back to normal! Based on your re-challenge results you can reintroduce the FODMAPS you tolerated well and test how frequently you can eat the ones you were mildly sensitive you.

It’s very important to keep a food diary at this stage, because you can try out different combinations and how frequently you can eat given FODMAPs.

If you had a strong reaction to one type of FODMAP please know that it might not be forever! When you feel ready, you can re-challenge it in a few weeks or months time. Your tolerance may have changed for the better!

The goal is you get to back to most normal, varied and nutritious diet possible, while keeping your symptoms under control. This is not a lifestyle diet or a way to lose weight, but an efficient way to identify your triggers.

bottom of page