15 January 2018

The 3 phases of the low FODMAP diet

3 PHASES OF LOW FODMAP DIET

By Erin Dwyer - Research Dietitian

What do you do when you feel better following a low FODMAP diet? Re-introduce FODMAPs! While this may sound illogical, it is important for a number of reasons, first and foremost to ensure your diet is minimally restrictive, while still providing adequate symptom control. Read on for a simple guide to the 3 phases of a low FODMAP diet.

1. Low FODMAP phase

This is to be commenced under the supervision of a dietitian for a period of 2-6 weeks.
During this phase you would use the Monash University Low FODMAP Diet App to choose
foods with a ‘green’ serving size. This means that you only eat foods in a low FODMAP serve.
But remember, a low FODMAP diet is not an elimination diet. Rather, it is a substitution diet,
whereby you swap one food for another, e.g. switch your daily apple for an orange, or swap
an onion for chives.


2. Re-challenge phase.
This stage involves reintroducing foods back into your diet in a methodical way to determine
which foods and FODMAPs trigger symptoms and which do not. Each FODMAP subgroup
should be challenged separately while your background diet remains low in FODMAPs. The
re-challenge phase is also best completed under the guidance of a dietitian, who will advise
you on when to re-challenge; which foods to re-challenge with (e.g. honey to test your
tolerance to excess fructose); the dose of re-challenge food to use, and the order of the re-
challenges. Remember to have a break of a few days between challenges to avoid any
crossover effects. A dietitian will also help you to interpret your re-challenge responses. It
takes most people around 6 to 8 weeks to complete the re-challenge phase.

3. Personalised FODMAP diet phase.

The third stage of the diet involves establishing your longer term, personalised FODMAP diet. Once your dietitian has interpreted your food challenge responses, you can begin to reintroduce foods and FODMAPs that were tolerated well in the re-challenge phase, and restricting ONLY the foods and FODMAPs that triggered your symptoms. It is important to remember that FODMAP tolerance can change over time, so if there are foods you didn't tolerate as well, try again in a few months to see if anything has changed. 

We understand it can be daunting to start re-challenging foods, especially if you are feeling well after following the initial low FODMAP diet, but there are important reasons why you should complete the re-challenge phase and expand your diet. To read more about these reasons, take a look at our previous blog posts on the topic. 

  • https://www.monashfodmap.com/blog/new-year-goals-to-improve-your-ibs-and/
  • https://www.monashfodmap.com/blog/dietary-fibre-series-prebiotic-fibre/
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