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FODMAPs - What are they?

The term FODMAP is being used in the media more often as people are becoming aware of IBS and ways they can manage it. You might have heard of a low FODMAP diet, or that certain foods are ‘FODMAPs’, or someone saying they have been ‘fodmapped!’. So, what are FODMAPs and what do they have to do with your gut?

First things first, FODMAP is an acronym:







These technical words are describing particular carbohydrates found in foods. These carbohydrates have been found to trigger gut symptoms for most people with IBS.

They do this because they are poorly digested. Digestion is all about breaking down the food we eat into small, simple substances which can then be absorbed and used within our body for fuel. FODMAPs that aren’t digested result in increased water in the gut causing diarrhoea, and/or result in increased gas as they are fermented by bacteria in the large intestine. Bloating, diarrhoea, increased with and abdominal pain are all common side effects that a person with IBS may experience after consuming foods high in FODMAPs.

Why do FODMAPS matter?

Do you regularly experience abdominal discomfort, bloating, gas, constipation, or diarrhoea? You may have irritable bowel syndrome. It is estimated that approximately 1 in 7 Australians suffer from IBS. Research around reducing IBS symptoms has proposed a low FODMAP diet as the most effective method of managing this condition. By reducing consumption of high FODMAP foods, symptoms of IBS can clear up in a few weeks.

What is a low FODMAP diet?

A low FODMAP diet is a diet designed to reduce the load of FODMAPs on your gut. A strict low FODMAP diet is a short-term measure to determine whether FODMAPs are the cause of your IBS symptoms and should be followed by a reintroduction and personalisation phase (described below). Low FODMAP diets can be difficult to follow correctly, confusing and restrictive if you are doing it alone. If you are suffering from IBS and wish to try the low FODMAP diet, it is important you seek help from an Accredited Practising Dietitian specialising in gut health.

A low FODMAP diet has 3 phases:

1) Elimination

This phase involves removing all high FODMAP foods from your diet for approximately 2-6 weeks to see if symptoms are resolved and let your gut rest. Finding appropriate alternatives to high FODMAP foods is important to prevent nutrient deficiencies – a dietitian can help you with this!

2) Reintroduction

This phase involves reintroducing FODMAP foods into your diet in a systematic way. Not all individuals with IBS will experience symptoms from all the FODMAP groups and may only experience symptoms when consuming excessive amounts. By reintroducing high FODMAP foods in particular quantities, this phase tests your tolerance and identifies which FODMAPs you are sensitive to. Tolerance to FODMAPs can change over time so this step should be repeated periodically.

3) Personalisation

The final stage involves customising your diet to include the FODMAPS that you can tolerate back into your diet.. Through reintroducing tolerated FODMAP foods, you will be able to enjoy a variety of foods to ensure your diet is nutritionally balanced while keeping your IBS symptoms well managed.

Why can’t I stay on the low FODMAP diet long-term?

This simple answer to this is because it is unnecessary. Most people with IBS can tolerate more FODMAPs in their diet than a strict low FODMAP diet allows. Why miss out on the foods you enjoy for no benefit?

Secondly, a strict low FODMAP diet limits the variety in your diet. Different foods contain different vitamins, minerals and nutritious compounds. If you have a varied diet you are more likely to get all the nutrients that your body needs. On the flip side, if you have limited variety in your diet it is more likely that you will develop a nutrient deficiency.

Fibre and calcium are two important nutrients that may be lacking in a low FODMAP diet. Calcium is found in dairy food sources and fibre is found in many vegetables and wholegrain foods which are avoided when maintaining a low FODMAP diet. Fibre is important for regular bowel movements and a healthy gut, while calcium is needed for strong, healthy bones and teeth, and for our nervous system. It is important that appropriate alternatives can be included while on a low FODMAP diet and a dietitian can help you find these!

Many high FODMAP foods are also high in a type of fibre called prebiotics. These are important for a happy, healthy gut. Prebiotics provide food or fuel for the healthy bacteria that are found in your gut and help them to thrive. Removing all FODMAPS from your diet long-term may mean you are not getting enough of these prebiotics in your diet.

Individuals with IBS can prevent gut symptoms while consuming FODMAP foods that they can tolerate. Not all individuals will experience the same symptoms from the same FODMAP containing foods. And just because you are sensitive to a FODMAP at one point in time, does not mean that your sensitivity will last forever. It is important that your diet is tailored and customised to yourself and your own symptoms.

Top 3 challenges of the low FODMAP diet – Why should you seek help?

1) Hidden FODMAPs

FODMAPS can be found in many different foods and may be hidden in some food sources that are not as obvious. Having a dietitian who is knowledgeable on the low FODMAP diet can help ensure you are eliminating all sources in your diet and hidden traces are not causing your gut symptoms. That way, you will have a clear idea of whether the low FODMAP diet has helped your IBS or not.

2) Nutritional imbalances

As mentioned earlier, many nutrients can be lacking in a low FODMAP diet and finding suitable alternatives to these foods can be challenging. A dietitian can support you in finding appropriate alternatives to make sure you are getting all the nutrients that you need and that your final personalised diet is nutritionally adequate.

3) Falling off the wagon

The low FODMAP diet phases can take time and effort to complete. Having a supportive dietitian throughout this process can make this new way of eating easier by finding enjoyable alternatives that suit your lifestyle, support you in identifying why your symptoms could be persisting and tackling any challenges that occur along the way.

What if a low FODMAP diet doesn’t work?

For some individuals, the low FODMAP diet may not relieve IBS symptoms satisfactorily. It is important to consider other factors that may be causing your symptoms such as stress, caffeine, or fatty or spicy foods. Speak with your dietitian before ruling out a low FODMAP diet and see what other options could be appropriate for you.

So, you have IBS, what next?

Speak with an Accredited Practising Dietitian that specialises in IBS and gut health to see if the low FODMAP diet is suitable for you.

Sascha is a Monash certified FODMAP dietitian with 10 years of experience helping people just like you manage their IBS. Sascha offers a supportive and comprehensive approach to managing IBS in her 'Master Your IBS Program'. Learn more about the program by clicking here.


Dietitians Australia. 2020. FODMAPS and IBS – What’s the deal? Retrieved from:

Mahan LK and Raymond JL. (2017). Krause's Food and the Nutrition Care Process. (14th ed.). St Louis, Missouri: Elsevier.

Blaak, E. E., Canfora, E. E., Theis, S., Frost, G., Groen, A. K., Mithieux, G., Verbeke, K. (2020). Short chain fatty acids in human gut and metabolic health. Beneficial Microbes, 11(5), 411-455.


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