[Last updated 17th February 2017]
The FODMAP reintroduction plan is arguably the most important part of a low FODMAP diet .
The aim is to learn what your individual tolerance level is to different FODMAPs, and reintroduce some of your favourite foods as well.
But in order to be successful, it must be approached in a systematic fashion.
This is a detailed overview and FAQ of the reintroduction process.
- If You Prefer Video
- What is the FODMAP Reintroduction Plan or Challenge Phase?
- How Does It Work?
- Which Foods or Groups Should Be Challenged First?
- How and When to Reintroduce FODMAPs
- Tracking IBS Symptoms With a Food Diary
- What if You ‘Fail’ All Reintroductions?
- FODMAP Reintroduction Protocol and Recommendations
If You Prefer Video
What is the FODMAP Reintroduction Plan or Challenge Phase?
The FODMAP reintroduction plan is the second part of a low FODMAP diet, and refers to the strategic process of reintroducing FODMAPs to the diet.
It’s also known as the Challenge Phase, Reintroduction Phase, or Challenge Protocol. The terms reintroduce and challenge (or re-challenge) are used interchangeably.
Following this plan enables you to discover what exact FODMAPs trigger your IBS symptoms. By the end you should have a great understanding of what foods you can and cannot tolerate, and in what quantities.
Much like the elimination phase, it’s not easy. There are many guidelines to follow and it’s strongly recommended you do this with a FODMAP-trained dietitian where possible.
Summary: The FODMAP reintroduction plan is the second phase of a low FODMAP diet. Following this protocol enables you to see what foods you do and do not tolerate.
How Does It Work?
There are 10 FODMAP groups to be reintroduced, one at a time.
This must occur over a 3-day period, with 3 washout days in between groups. That is, set days where you completely return to a low FODMAP diet in order to ‘reset’ your digestive system.
A typical schedule may look like this, although this just a generalisation. Re-challenge is used interchangeably for reintroduce:
Image Source. Click to enlarge.
So if you are re-challenging for 3 days, and leaving a 3-day washout period, the re-challenge process for one group lasts almost a week. That means 10 FODMAP groups will take 9-10 weeks total, assuming no set backs.
If you do experience symptoms, you must wait until they settle before testing the next group. Usually the 3-day washout period is enough time, but not always.
Note that you should not re-challenge any FODMAPs until you are symptom-free (or as close as you can be). It’s also important during this period that you continue to follow a low FODMAP diet the entire time.
Summary: A total of 10 different FODMAP groups are reintroduced to the diet, one at a time. Each group is re-challenged over a 3-day period, followed by a 3-day washout period. So it takes at least 9-10 weeks to do all groups.
Which Foods or Groups Should Be Challenged First?
The most appropriate foods for this phase are those that contain only one FODMAP group.
This ensures that if you do have a reaction, it’s obvious what FODMAP was the culprit. Here’s some examples from FODMAP dietitian Lee Martin:
There are 5 separate re-challenges for fructans because they occur in a wide variety of fruits, vegetables and grains. Fortunately there’s only one re-challenge for each of the remaining FODMAPs; the exception polyols which has two types (sorbitol and mannitol).
Example Reintroduction Schedule
Here is an example of a full schedule to follow from Lee Martin and A Little Bit Yummy.
It contains recommended foods and quantities. You can start with whichever group you wish, but it may be easier to start with lactose or fructose as they are quite straight forward:
Click to enlarge.
*Clarification: 1/2 cup (70 grams) of sweet potato is low FODMAP, but 3/4 cup (100+ grams) is high in polyols, making it high FODMAP. Hence you can rechallenge with the 100 gram amount. The same goes for 1/8 avocado (low FODMAP) vs 1/4 avocado (high FODMAP).
So it’s important to increase the number of foods that contain the FODMAP you are testing, and then assess your response.
If you DON’T get symptoms:
- Increase the amount you are testing until you’ve done 3 days. After this, do the 3 washout days and then move onto the next FODMAP challenge.
- It’s best not to eat the previously tested food often, if at all, for the remainder of the reintroduction period (even if it did not cause you symptoms). This simply minimizes potential complications during the process.
If you DO get symptoms:
- Wait until you are symptom free, then reduce the serving size to half and challenge again,
- Try another food from within the same FODMAP group to confirm the results of the first challenge.
- Or you can assume that FODMAP is a definitely a trigger for you and move onto challenge the next FODMAP group (after waiting for symptoms to resolve of course).
It’s recommended that you challenge any problem FODMAPs again in the future (a year or so), as sensitivity to FODMAPs may change over time.
Summary: Reintroduce whichever FODMAP group you prefer first. Just ensure you only test with foods that contain one type of FODMAP.
How and When to Reintroduce FODMAPs
There are two main options for reintroducing FODMAPs. It should always be done at home where you are in control of the portions and ingredients.
- Alongside: Prepare the FODMAP containing food alongside your regular meal (that you know does not cause symptoms). For example 1 teaspoon of honey with your dinner. This allows you to easily increase the portion size of the FODMAP you are testing .
- Mixed: Mix or add the FODMAP food you are testing into your meal or snacks. For example if testing avocado you could add it as part of your favourite dip. This is more realistic to the way you would actually consume that food, but is less straightforward.
The best time of day to re-challenge depends on your personal preference and when you would typically eat that food.
But I usually recommend doing so in the early evenings when at home. There is no possibility of being ‘caught out’ when at work, and allows enough time to notice symptoms before bed.
Summary: Either reintroduce groups alongside or mixed in with the meal. Typically it’s best to test in the early evening when you are home.
Tracking IBS Symptoms With a Food Diary
A common question is when will the symptoms show after testing a food?
This varies from person to person and also depends on the severity of the reaction (if there is one). Patients report symptoms anywhere from 30 minutes, the next morning or even a couple of days later.
Just like the elimination phase, it’s critical to keep a food and symptom diary during the entire reintroduction plan. Recording what you ate, what quantity, and what symptoms resulted helps you to identify patterns you might otherwise have overlooked.
Note that for some individuals there may be FODMAP groups and foods that will always cause symptoms, regardless of the amount. If you’re highly sensitive to a particular food, you shouldn’t eat it anymore.
Summary: Symptoms from reintroducing a group can vary from 30 minutes until several days later. Keeping a food and symptom diary will help you recognise patterns.
What if You ‘Fail’ All Reintroductions?
There are numerous reasons why someone may react to every single re-challenge food, even in small quantities.
Consider the following:
- Testing high amounts of the re-challenge FODMAP: Always start with a small amount first as that may be your threshold. If you don’t experience a strong reaction then in increase it the following day. For example start with ¼ avocado, then progress to ½.
- Not remaining on a low FODMAP diet: During the entire reintroduction plan you must continue to follow a strict low FODMAP diet, as you were during the elimination phase. After a food has been tested do not add it back into your diet you’ve finished re-challenging the remaining groups.
- Choosing inappropriate foods: You must re-challenge with foods that contain only one FODMAP. If testing fructose, for example, pear would be a poor choice because it contains both fructose and polyols. Honey or mango only contain fructose and are therefore a good choice.
- Unintentionally changing your routine: Other changes and stressor can trigger digestive symptoms. Ensure you don’t increase the amount of smoking, alcohol, or caffeine you consume during the reintroduction plan. Stick to your usual eating pattern, and avoid unusually large meals or testing FODMAPs on an empty stomach.
- Medical conditions or additional intolerances: If you are doing everything correctly, it’s possible you may have additional intolerance issues that should be investigated with your doctor. This includes a food chemical intolerance (such as salicylate, amine, glutamate or histamine intolerance), small intestine bacterial overgrowth (SIBO), or even inflammatory bowel disease such as Crohn’s disease.
Unfortunately, while the low FODMAP diet is highly effective, it’s not a cure-all.
Research shows it doesn’t work well for 1 in 4 patients, although often this is because they were not strict enough during the process.
However, there are some who will not improve despite doing everything correctly.
FODMAP Reintroduction Protocol and Recommendations
While I’ve touched on the fundamentals, it’s much easier to carry out following a complete FODMAP reintroduction protocol.
If a FODMAP-trained dietitian is not accessible, I recommend the book Re-Challenging and Reintroducing FODMAPS: A self-help guide to the entire reintroduction phase of the low FODMAP diet (affiliate link).
It provides a full protocol to follow and is authored by FODMAP-specialist dietitian Lee Martin.
As always I also strongly recommend investing in the Monash FODMAP app for your phone or tablet.
Monash University is the home of FODMAP research, and the app provides the most up-to-date FODMAP food database and recipes available.