Meal with high fodmaps

What is the low FODMAP diet?

What is it the low FODMAP diet?

The low FODMAP diet has been getting some more traction recently, and for good reason! It has been shown to help manage IBS-type symptoms in those with IBS but also in the context of endometriosis and even runner’s gut.


What are FODMAPs?

FODMAP is an acronym for four groups of short chain carbohydrates, or sugar molecules that are found naturally in a wide variety of foods.


FODMAPS stands for:








explaining fodmap acronym



In some people, FODMAPs can trigger digestions issues such as nausea, reflux, bloating, cramping, gas, constipation and/or diarrhoea.

They do this through two key mechanisms:

1. Some FODMAPs are highly osmotic.

This means that they draw water into the intestine. As this happens, it creates pressure within the gut. The gut is triggered and this can lead to diarrhoea.

2. FODMAPs are fermentable.

As their name suggests, FODMAPs are fermented by the flora in your large intestine. Essentially, your gut bugs are feeding on the FODMAPs as as they do, they produce gas. For some people this can result in bloating and cramping due.

Monash University have put together a great summary video explaining the basic mechanisms of how FODMAPs can trigger gut discomfort.



A Little More on the Different Types of FODMAPs


Oligosaccharides aren’t actually fully digested by anyone! However, those with a sensitive gut can experience much worse symptoms. Your tolerance to oligosaccharides will depend on your gut flora (think of your gut microbiome as your fingerprint – everyone is slightly different!) and your tolerance threshold (how well you can tolerate the accumulation of oligosaccharides over the day or week).



Lactose is our di-saccharide because it contains two sugar molecules. Some people do not tolerate lactose as they are unable to properly digest the double sugar molecules. Lactase is an enzyme produced by your body for the purpose of helping you digest lactose. Sometimes consuming lactose products with a lactase supplement can help your symptoms.



Fructose is our monosaccharide as it’s only got one sugar molecule. When it comes to fructose, the ratio of fructose and glucose in a food matters. Glucose is found in varying amounts in foods, however, if fructose is consumed in higher amounts than glucose within food.


Unfortunately, this doesn’t mean that we can assist symptoms by simply adding glucose to a fructose food. It would make sense in theory, however, research hasn’t shown much promise.



There are two key sugars from the polyol group:

  • Sorbitol

  • Mannitol

Most people struggle to absorb polyols, which is one of the reasons they are commonly used as artificial sweeteners (e.g. stevia or Splenda). Because they aren’t absorbed, they cont contain calories.


Meal with high fodmaps


What’s the process?

If you suspect that your IBS-symptoms are caused by FODMAPs then the first step is to book an appointment with your GP and Dietitian.


IBS can feel very similar to some more nasty conditions, so it is important to rule anything more serious out first with your GP.


In your dietitian session, it will also be important to first assess other lifestyle factors as gut health is more complex than food intolerances such as FODMAPs. If you and your dietitian do decide to go down the FODMAP route, the first step will be an elimination diet followed by a testing phase.



During this phase you will remove all FODMAPs for 4-6 weeks. Your dietitian will work with you to ensure that your diet is adequate in key nutrients and energy.



Once you’re through the elimination phase, you’ll test different FODMAP foods in increasing doses to find your individual tolerance level. There is a very specific procedure to this to ensure you have enough data to build a maintenance diet from.



Once we know what FODMAP and what dose your body is reacting to, we can develop an understanding of a maintenance diet. It’s important to note, that this will actually likely change over time and can be impacted by lifestyle factors such as stress, sleep and exercise.


What’s the risks?

If you’re struggling with IBS symptoms, then it makes sense to jump in and cut them out right away, however, done poorly, a low FODMAP diet could end up contributing to worse gut health long term!


This is because these foods are actually really important for establishing and maintaining a healthy microbiome. Cutting them out long-term strips your diet of key food for your gut bugs and fibre diversity and variety for your overall bowel function.


If you’re looking at following the process of a low FODMAP diet to find your triggers, it’s going to be essential that you work with a dietitian with knowledge in this area (like us!).


Up Next:

For a list of the foods that contain high amounts of FODMAPs head to our post ‘FODMAP food list‘.

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