How to Challenge a FODMAP

The aim of the reintroduction phase is to give you a better understanding of how your system reacts to each of the FODMAP groups. With this knowledge you are able to modify your long term diet to have as much variety as possible, while still minimizing symptoms.

When to start

You are ready to move into reintroduction challenges after about 2-6 weeks on elimination and a minimum of at least five days in a row of significantly reduced symptoms. Since unexplained symptoms will interfere with clear answers about your tolerances, it is important to have symptoms well managed before beginning challenges. If after 6 weeks your symptoms are not settling it would be time to do some trouble shooting.

Timing of challenges

Stress, hormones and illness can interfere with challenge results. Try to choose a time when you feeling relatively relaxed and in a comfortable setting. If you are unwell or having a stressful time, it is worth delaying a challenge until you feel more relaxed.

Choosing foods

The challenge phase is about finding out how you react to each individual FODMAP group. You will then be able to use this information in the long term for determining which foods you are likely to tolerate in small, medium or large amounts. This means you are testing FODMAPs, and not foods.

It is important to test one FODMAP group at a time. This way if you do react you will know which FODMAP group triggered your symptoms. To do this choose foods that only contain one type of FODMAP. Mango for example only contains fructose, so if you react to mango you will know it was fructose that triggered it. On the other hand, an apple contains both fructose and sorbitol, so if you react to an apple, you won’t know which of these two FODMAPs is the problem. This may involve eating foods you wouldn’t normally eat, but it will give you the greatest information about your triggers.

Order of challenges

The order you choose to do challenges doesn’t really matter too much. Fructose and lactose are two of the simpler challenges, so this is sometimes a good place to start.

What can you eat during challenges?

During challenges, with the sole exception of the challenge food, it is important to keep the rest of your diet low FODMAP. Even if you have successfully completed a challenge, you still need to remove this FODMAP group during other FODMAP challenges.

Keep other non-FODMAP triggers, like coffee, alcohol, spicy foods or carbonated drinks, consistent during the testing phase. Additionally, do not take unnecessary supplements, medications or probiotics as these may also cloud results.

When to stop a challenge

I encourage my patients to rate their symptoms as mild, moderate or severe. With this in mind, the general rule is to stop a challenge if “moderate symptoms” occur.

Tip: FODMAPs do not cause permanent physical damage or injury, the goal of the low FODMAP diet is to minimize symptoms to a point where they allow you to improve your overall quality of life. A little bloating occasionally is not a huge issue, however you do want to prevent your IBS from interfering with your social life, intimate life or work life. This means that “moderate symptoms” is a subjective measure and only you can determine where the balance lies between what you want to eat versus which symptoms you are willing to put up with.

If you react

If you have moderate symptoms, you can stop the challenge. Take the test food back out of the diet and wait until the reaction goes away. Wait until you feel well again. Then have at least three days with no or minimal symptoms before starting the next test.

If you do not react

If there is NO REACTION during the challenge, you can consider the challenge complete. You still need to stop eating the challenge food and wait 3 days before beginning the next challenge.