An Overview of the Low FODMAP Diet

Never heard of a FODMAP before now? That’s ok. The low FODMAP is not a mainstream diet. It is a medical diet that was developed by the gastroenterology team at Monash University in Melbourne, Australia over the past 10 years to treat people with IBS. A body of high quality research studies now show that the Low FODMAP Diet can be used as a first line of therapy for IBS (Garret, 2017). It now comprises a key component of the dietary guidelines for IBS in many countries worldwide, such as in the UK (NICE, 2015).

The Low FODMAP Diet is now an internationally accepted dietary management strategy for IBS (Garrett, 2017).

Until now, the dietary management for IBS has not been very effective. Patients diagnosed with IBS had to figure out food intolerances on their own. They needlessly restricted the wrong foods, relied on medications and many still suffered.  I still see this with new clients joining my practice.

Support From a FODMAP Trained Dietitian

Research shows that the success of patients with IBS is largely reliant on the support provided by a dietitian with FODMAP experience.

The skill set of the dietitian is paramount to the success of the low FODMAP diet. (Garrett, 2017)

I am a Monash University FODMAP Trained Dietitian and I offer nutrition counselling across Canada by video and phone. In my practice, I work exclusively with people who have IBS. I absolutely LOVE getting people started on the low FODMAP diet and providing support along the way. Before starting the low FODMAP diet, it is essential to be properly diagnosed with IBS using the Rome IV Criteria by your medical doctor and have other medical conditions like celiac, ulcerative colitis, Crohn’s disease, cancer, and others ruled out.

First, Eat for Good Digestion


Aim for 2-3 liters of water daily.

Here are some digestive strategies to start with. For some people, this may be all you need in order to feel better. For others, this won’t be enough. But, it is a good place for everyone to start.

  • Avoid skipping meals
  • Eat a minimum of 3 meals a day
  • Drink at least 2 liters of fluid daily, ideally water
  • Limit alcohol
  • Get the right amount of fiber (about 25 grams for women and 30 grams for men)
  • Avoid chewing gum or artificial sweeteners that contain polyols (sorbitol, xylitol, mannitol)

1. Low FODMAP Phase (aka Elimination)

This part of the diet makes all of the headlines! During the Low FODMAP Phase, you limit foods high in FODMAPs and eat mostly foods that are low in FODMAPs. Your goal is to reduce your overall FODMAP load to a point where your symptoms improve. The degree to which you will need to reduce FODMAP is different for everyone. Despite what you may read online, it’s not really a “one size fits all” type of diet. In my practice, I tailor the Low FODMAP stage to be the least restrictive to get adequate symptom relief. To find out what a FODMAP is, read my previous blog titled, What is a FODMAP.

Moving on. A great place to start is by downloading the Monash University Low FODMAP app. The app has a “traffic light” categorization system:

  • Green light portion – low in FODMAPs
  • Yellow light portion – moderate amounts of FODMAPs
  • Red light portion – high in FODMAPs

Another great app with a different selection of foods is FODMAP Friendly. They use a clever percentage system. Both apps use trustworthy testing methods and cover a growing range of foods.

What about foods that have not been tested?

For foods that have not been tested by either Monash or FODMAP Friendly, you can either avoid them or work with a knowledgeable dietitian. It is difficult to predict the FODMAP content without testing. Monash and FODMAP Friendly are actively testing and adding more foods to their apps, so keep your eye out for new additions.

How long?

According to Monash University, the Low FODMAP Phase should last between 2-6 weeks. If after a few weeks of closely following the diet, you have not experienced symptom relief, you should work closely with your dietitian to make sure that you are following the diet correctly. Your dietitian will also be able to offer other dietary and lifestyle recommendations such supplements, functional fibres and/or probiotics that may help. If after 6 weeks, you have not experienced good symptom relief, work with your dietitian and doctor because this is not meant to be a permanent diet. You should be assessed again to make sure you don’t have something else going on.

Low FODMAP Granola

Low FODMAP granola, an orange and lactose free milk or almond milk is a delicious low FODMAP breakfast.

Rechallenge Phase

Now you need to put on your scientist hat. You will systematically reintroduce higher FODMAP foods to determine which foods you tolerate and the amount.

The re-challenge phase can finally provide patients with some certainty around their dietary intolerances, of which patients have often struggled for many years  (Tuck, 2017).  

This is the really interesting part as you will finally discover which foods trigger symptoms. This phase tends to last about 5-6 weeks and looks very different for everyone.  The foods that you choose to rechallenge and the amounts can be tailored by your dietitian according to what you miss most and your symptoms.

If you experienced symptoms from eating a higher FODMAP food, you can try it again a few weeks or months later. Your tolerance for FODMAPs can change over time.

Adapted Low FODMAP Diet

This is where you put it all together and learn how to incorporate everything you have discovered over the past few weeks. You may find that you can eat some foods with reckless abandon and other you can’t touch with a 10 foot pole, but many will fall somewhere in between. You will still need to mindful of the various high FODMAP foods you eat in one meal or one day. Again, everyone is different and your tolerance for foods can change over time.


In the long run, it is important to eat higher FODMAP foods in amounts that you can tolerate.

In Summary

As you have noticed, the low FODMAP diet is a complex medical diet! If you don’t follow the diet accurately, your symptom improvement may be limited. With the help from an experienced dietitian, the low FODMAP diet can be a real game changer. Going through all of these steps is challenging and requires a lot of learning and detective work that a FODMAP trained dietitian can help with. You don’t have to do this alone!

About Audrey:

I am a registered dietitian who specializes in IBS and the low FODMAP diet. I am based in Edmonton, Canada and I offer nutrition counselling by phone and video to anyone across Canada. If you are looking for help, have a look at my nutrition counselling page or get in touch for a free appointment.


Barrett, J.S. How to institute the low FODMAP diet.  Journal of Gastroenterology and Hepatology.  2017;21 (suppl.1)8-10.

Retrieved from: NICE: National Institute for Health and Care Excellence.  Irritable bowel syndrome in adults: diagnosis and management, 2017.

Tick, C. and J. Barrett.  Re0challenging FODMAPs; the low FODMAP diet phase tw0.  Journal of Gastroenterology and Hepatology.  2017; 32(supple.1): 11-15.


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By |2018-12-18T19:05:40-07:00April 23rd, 2017|FODMAP articles|0 Comments

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