Testing FODMAPs: How does the reintroduction phase work?

How To Test FODMAPs: Reintroduction Phase

Well done on surviving the elimination phase! If your symptoms have settled then it is now time to regain your food freedom, and tackle the FODMAP re-challenge and reintroduction phase to help you identify your trigger foods.

The goal of this phase is to develop an understanding of your individual tolerance levels to each of the FODMAP groups  (1 2). You might discover that you can tolerate a little bit of some FODMAP groups, can eat other FODMAP groups freely, and need to stay on the low FODMAP plan for FODMAPs that trigger symptoms. The good news is that most people find they can successfully reintroduce a couple of FODMAP groups and create a diet with a lot more variety.

Reintroduction Resource

Registered dietitian Lee Martin is a low FODMAP researcher who specialises in the FODMAP reintroduction process. He has written a best practice guide that walks you through the testing and reintroduction process by providing step-by-step guidelines, and a wider range of high FODMAP foods you can use for testing. 

Please note that this article does not replace the advice or expertise of a registered dietitian, who specialises in the low FODMAP diet. 

Why is Working With a Dietitian Important?

Not everyone is lucky enough to have the help of a FODMAP trained dietitian but if you can, it is a good idea to seek their help. They will be able to work out the type and amount of FODMAPs you can tolerate based on your own personal needs, preference and medical history  (1 2 3). 

Why Reintroduce FODMAPs?

Our gut bacteria love to feast on high FODMAP foods. FODMAPs often act like prebiotics and have a positive effect on our gut health (1 2 3). This means restricting FODMAPs long term could have a negative impact on your overall health.

The low FODMAP diet is also restrictive and socially isolating, as it can be very difficult to eat out or attend potlucks while on the elimination phase. With your new found food freedom you will be able to enjoy a wider range of foods at these events.

Overall long term health and wellbeing can be affected by a strict low FODMAP diet. Reintroducing some high FODMAP foods increases the variety of your diet, and helps it remain nutritionally adequate in the long term.

What To Do When You Find A Trigger Food

The reintroduction phase is a bit like being on a roller coaster, it’s both exciting and terrifying all at the same time. While you might find a few FODMAP friends, at some point you are likely to find a high FODMAP food that triggers your symptoms. Don’t panic! These symptoms will pass within a few days. Focus on the positive (I know this can be hard to do!), which is that you now have a confirmed trigger that you can actively manage. You still may be able to reintroduce this food back into your diet but at a lower level.

How does the reintroduction phase work?

The reintroduction phase is a series of food challenges that help you test your tolerance levels to each FODMAP group. One FODMAP group is challenged per week and it is tested for 2 to 3 days during that week (1  2).

If you don’t react to a FODMAP group you can reintroduce these foods once you finish the challenges. If you have a mild reaction then you can reintroduce these foods in small amounts as you feel comfortable. If you strongly react to a FODMAP group then these foods will remain out of your diet to keep your symptoms settled in the long run.

There are two ways you can test FODMAPs. This is the first way:

 Test Schedule One

Re-Challenge Day Re-Challenge Day Re-Challenge Day Washout Period Washout Period Washout Period If symptom free, start the next test.
Small FODMAP Portion (moderate amount of FODMAPs) Medium FODMAP Portion (high amount of FODMAPs) Large FODMAP Portion (very high amount of FODMAPs)        
No symptoms or mild symptoms, continue. Severe symptoms, stop. No symptoms or mild symptoms, continue. Severe symptoms, stop. Stop test after completing day three and record symptoms       Start next FODMAP test once symptoms have been settled for three days.

 If you are concerned about testing three days in a row, you can use an alternative testing schedule like test schedule two (4). You can also complete a more gentle reintroduction, where you consume a small FODMAP dose for three consecutive days, and then increase the serving size if it is well tolerated (5).

 Test Schedule Two

Re-Challenge day: Eat challenge food & monitor symptoms Rest day: Monitor symptoms Re-Challenge day: Eat challenge food & monitor symptoms Rest day: Monitor symptoms Re-Challenge day: Eat challenge food & monitor symptoms Rest day: Monitor symptoms Rest day: Monitor symptoms
Small FODMAP Portion (moderate amount of FODMAPs)   Medium FODMAP Portion (high amount of FODMAPs)   Large FODMAP Portion (very high amount of FODMAPs)    

This testing schedule should be used when testing fructans and GOS (5). These FODMAPs move through our digestive system more slowly, and it may take longer for them to trigger a reaction. Also keep in mind that your dietitian might create a testing schedule that is more suitable for your personal needs.

Important Challenge Instructions

Between each re-challenge test you need to be symptom free for at least 3 days, before you start testing the next FODMAP group. If you get moderate to severe symptoms after the first or second test day of eating the challenge food, you should stop the test and consult with your dietitian.

Once you have finished testing a food, do not add it back into your diet until you have finished testing all of the FODMAP groups.

A dietitian can help you tailor the challenges to suit your needs, and they may recommend different re-challenge foods or lower doses.

What are Challenge foods?

Challenge foods are foods that only contain one of the FODMAP groups  (1 2 5).  

Re-Challenge Schedule & Food Example

Re-challenge & FODMAP
Recommended Challenge Foods
Re-Challenge 1: Fructose

*1 teaspoon of honey increasing to 2 tablespoons of honey

*1/4 a medium sized mango increasing to 1 medium sized mango 
Re-Challenge 2: Sorbitol (Polyols)

*3 blackberries increasing to 10 blackberries

*1/4 of an avocado increasing to a whole avocado

*1 fresh apricot (use the same serving size for each test day as apricots also contain fructans in larger serves).

*Some dietitians may also use coconut or sugar free mints containing sorbitol.
Re-Challenge 3: Mannitol (Polyols)

*1/2 Portobello mushroom increasing to 1/2 cup serve

*100g of sweet potato increasing to 200g serve

*30g cauliflower increasing to 90g serve

Re-Challenge 4: Lactose (Disaccharides)

*125ml milk increasing to 375ml of milk

 *1 scoop of ice cream increasing to 3 scoops

*200ml of yoghurt (just watch out for added high FODMAP ingredients in the ice cream and yoghurt) 
Re-Challenge 5 & 6: Fructan Bread, Cereals, Grains (Oligosaccharides). Test two foods from this group.

*1 slice of white wheat bread increasing to 3 slices of wheat bread

*50g wheat pasta increasing to 150g (use the cooked weight of the pasta).
Re-Challenge 7 & 8: Fructan Vegetables (Oligosaccharides). Test two foods from this group.

*1/4 of a clove of garlic increasing to 1 clove of garlic

*1/4 of a medium leek increasing to 1/2 whole leek (white and green sections)

*1 tablespoon onion increasing to 1/2 onion 
Re-Challenge 10: Galactans (GOS – Oligosaccharides)

*2 tablespoon serve increasing to 6 tablespoon serve of chickpeas or canned black beans

*Almonds (increase from 15 nuts to 25 nuts)

*Boiled red lentils (increase from ½ cup cooked) 
Re-Challenge 10: Fructose & Sorbitol (only complete if you passed both individual FODMAP tests) *½ apple or pear increasing to one whole apple or pear.

(Table References:  4, 5)

For a full list of FODMAP foods you can test with, please see Lee Martin’s Re-challenging and Reintroducing FODMAPS Guide.

Testing fructans at different levels means you are more likely to find a fructan level you can tolerate.

Once you have identified which FODMAP groups are unlikely to trigger your IBS symptoms, you can start slowly adding them back into your diet under the advice of your dietitian, and move onto a long term modified low FODMAP diet.

Happy testing! I hope you enjoy finding your food freedom while maintaining control over your IBS symptoms.


What happens if you react to all the challenge foods?

If you react to all of the re-challenge foods it can mean that the reintroduction phase is not being properly carried out, or that there are additional medical conditions, or food sensitivities that need to be considered. Here are some of the common reasons why you could be reacting:

  • Choosing the wrong challenge foods.

Make sure you and your dietitian are choosing challenge foods that only contain one FODMAP  (3). For example, a pear would not be a good re-challenge food when testing excess fructose as it contains high levels of both fructose and polyols. If you are trying to test fructose it would be better to choose honey or mango as the re-challenge food as they only contain excess fructose, and will give you a clearer indication of your fructose tolerance levels.

  • Not sticking to the low FODMAP diet while undertaking the FODMAP re-challenges

You need to follow a strict low FODMAP diet while completing the re-challenge phase. This means eating low FODMAP foods and using low FODMAP portions sizes while you do your challenges except for your challenge food. Then when you experience symptoms after eating a challenge food, you can be sure the reaction is from that and not something else you have eaten.

It is also advised to avoid eating out and drinking too much alcohol or caffeine, which could skew the results if you react. Alcohol and caffeine are gut irritants even though they are generally low FODMAP  (6 7). If you think alcohol or caffeine might be additional IBS triggers, then you can test them at the end of the reintroduction phase with the help of your dietitian.

  • Starting the re-challenge test with a high amount of the challenge food.

When testing a challenge food start with a small amount and then increase the amount on the next re-challenge day if you don’t have a severe reaction. For example, if you start by testing one whole clove of garlic your digestive system might freak out. Instead start with ¼ clove per serve and then ½ a clove – you might discover that you can tolerate a small amount and add a little bit back into your diet. Your dietitian can help you decide what testing amounts are appropriate for you.

  • Additional intolerances or medical conditions that need to be taken into consideration.

If you find you cannot tolerate any FODMAPs (despite having the guidance of a FODMAP trained dietitian), then further investigation is needed (8  3). It is possible that you could have additional sensitivities to gluten, have food chemical intolerances (histamine, salicylate, amines, glutamates, sulphites), small intestine bacterial overgrowth (SIBO) or another condition that needs treatment (8 3).



1. Mansueto, P., Seidita, A., D’Alcamo, A., Carroccio, A. Role of FODMAPs in Patients with Irritable Bowel Syndrome: A Review. Nutrition in Clincial Practice Journal. 2015-02-18. DOI: 

2. Mullin, G., Shepherd, S., Roland, B., Ireton-Jones, C., & Matarese, L. Irritable Bowel Syndrome: Contemporary Nutrition Management Strategies. Journal of Parenteral & Enteral Nutrition. 2014: Volume 38: Number 7. 781-799. DOI: 10.1177/0148607114545329. Retrieved from http://pen.sagepub.com/content/38/7/781.abstract

3. Scarlata, K. Low FODMAP Diet is Not a Forever Diet. Well Balanced. 2014-09-02. Retrieved from:http://blog.katescarlata.com/2014/09/02/low-fodmap-diet-forever-diet/. Retrieved on: 2015-03-21. (Archived by WebCite® at http://www.webcitation.org/6XD0gY6EH)

4. Martin, L. Re-Challenging & Reintroducing FODMAPs: A guide to the whole reintroduction phase of the low FODMAP diet. Lee Martin. 2015. Retrieved from:http://www.reintroducingfodmaps.com/welcome.html. Retrieved on: 2015-12-07. (Archived by WebCite® at http://www.webcitation.org/6dbukJJ4o)

5. Tuck C., & Barret, J. Re-challenging FODMAPs: The low FODMAP diet phase two. Journal of Gastroenterology and Hepatology. 2017: Volume 32: Issue 1, p. 11-15. Doi 10.1111/jgh.13687

6. Monash University App.  Food GuideThe Monash University Low FODMAP Diet App. 2014: Edition 4. Date retrieved: 2015-03-05. Retrieved from :http://www.med.monash.edu/cecs/gastro/fodmap/iphone-app.html. Accessed: 2015-03-05. (Archived by WebCite® at http://www.webcitation.org/6Wog73c8B)

7. BPACnz. Irritable bowel syndrome in adults: Not just a gut feeling. Best Practice Journal. 2014: Issue 58. 14-25. Retrieved from http://www.bpac.org.nz/BPJ/2014/February/ibs.aspx

8. Gibson, P., Barrett, J. & Muir, J. Functional bowel symptoms and diet. Internal Medicine Journal. 2013: Issue 42. 1067-1074. DOI:10.1111/imj.12266. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/24134168

Post your comment


  • Contented Belly 18/05/2015 7:48pm (3 years ago)

    Hi Alana, thanks for this post. I went through the process of introducing foods back into my diet after my elimination phase and the testing schedule was the same advice given by my nutritionist. It made having fructose malabsorption easier when I was able to increase what I was able to eat.

    • Alana Scott 18/05/2015 8:26pm (3 years ago)

      Glad you made it through re-introduction successfully :-)

  • Kim J 21/07/2015 10:48pm (2 years ago)

    Hi Alana, great post! I'm in week 2 (sorbitols) of the re-introduction phase after a 6 week elimination period and am wondering if 2-4 dried apricots means 2-4 dried apricot halves (as this is how they are typically packaged), or 2-4 dried whole apricots meaning 4-8 halves? Thank you!!

    • Alana Scott 21/07/2015 10:59pm (2 years ago)

      Hi Kim,
      I believe 2-4 dried apricots means the 1 to 2 whole dried apricots so that would 4 to 8 dried halves. Hope that helps! Good luck with the reintroduction process. :-)

  • Sarah 11/10/2015 6:26pm (2 years ago)


    firstly thanks for posting this. It is very helpful to read as it helps with understanding how the fodmap diet actually works which until recently was a bit of a mystery to me but I am starting to get it as I read more helpful resources such as your post.

    I am in the unfortunate position of not having access to a fodmap trained dietician and therefore have no choice but to go it alone .

    I read that introducing a challenge food should be attempted when there are no IBS symptoms present but I am assuming that as this may not be possible for many people like myself, who may find a reduction in symptoms and relief from the most unpleasant symptoms during the elimination phase but that they may not entirely go away, that you can still attempt a reintroduction whilst your symptoms are reduced?

    I have considered the fact also that whilst my diet is limited at present and as far as I know low fodmap, I may be eating foods that have fodmaps that I am unaware of or have not been tested yet.

    this is not easy

    • Alana Scott 11/10/2015 8:30pm (2 years ago)

      Hi Sarah,
      You have asked a really good question. The first thing I would suggest you check is that you are not consuming other additional trigger foods that might be making your IBS worse - check out this article http://www.alittlebityummy.com/high-fodmap-foods-other-common-ibs-food-triggers/ If you think one of the foods is triggering symptoms then try removing it from your diet. You also might want to check that you are sticking to the recommended portion sizes for low FODMAP foods as listed in the Monash Low FODMAP app. There are a few other things to check as well so have a look at this article http://www.alittlebityummy.com/7-reasons-why-the-low-fodmap-diet-might-not-be-working/

      If you think your IBS symptoms are as settled as they are going to get then you can try reintroducing foods. I would recommend you start with a very small serve of the test foods and work your way up. That way you are maximising the chance of finding a level of the food you tolerate. I would also recommend you leave slightly longer between testing each FODMAP group. This is to make sure your symptoms are as settled as possible before the next test.

      I know it is not easy but hopefully you will be able to make some progress. Just keep going as you are doing really well. Let me know if I can help you any further.

      Alana x

  • Sarah Berriman 15/10/2015 12:35pm (2 years ago)

    Hi Alana

    Thank you very much for your replies to this and my other question on another post.

    Your answers are very helpful and I am reading the articles you suggested and linked to above and will have a think about things.

    I will let you know how I get on if that is okay.

    best wishes


  • Sarah 15/10/2015 12:39pm (2 years ago)

    Hi Alana

    Thank you very much for your replies to this and my other question on another article post.

    They were both very helpful and I am reading the articles you suggested in the links above.

    I will have a think about things.

    I will let you know how I get on if that is okay.

    best wishes


    • Alana Scott 15/10/2015 8:20pm (2 years ago)

      Hi Sarah,
      I would love to hear how you get on. Please let me know if there is anything I can do to help. You can also email me through the contact page if you need to get in touch. I look forward to hearing from you in the furture.
      All the best,

  • Jon 21/10/2015 1:22am (2 years ago)

    Thank you so much for this article. I've been using it for 3 months, so I nearly have it memorized by now. I live in Japan and can't find any help in my city, not for lack of trying. The medical culture is just very different here. Long story short: this article is the most complete reintroduction guide I've found, and I'm feeling better each week. Thank you.

    • Alana Scott 26/10/2015 8:23pm (2 years ago)

      Hi Jon,
      I'm so glad you are finding the article and website a useful resources. It sounds like you are doing a great job managing FODMAPs and I am excited that you are starting to feel much better. Please let me know if there is anything else I can do to help.
      Kind regards,

  • Anna 21/03/2016 4:26am (20 months ago)

    Is there any reason for the order of reintroduction? For example, could I start with Galactans, since they are usually a pretty big part of my diet and I really want to know whether or not I get to keep eating legumes?

    • Alana Scott 21/03/2016 11:54pm (20 months ago)

      Hi Anna,
      You can start with whatever FODMAP group you choose. Just remember to wait until symptoms have settled before testing the next FODMAP group (this is normally a 3 day washout period). Once you have tested a food remember to remove it from your diet until you have finished the rest of the re-challenge tests. This is important because many people find they can consume small amounts of each FODMAP group but have issues when the have too many FODMAPs in one day. I hope that helps!

  • Liz 14/04/2016 1:29pm (19 months ago)

    Hi, I'm really confused to see Buckwheat listed as a re-challenge food! I've been on the strict elimination phase for about 3 months and keep getting close to giving up. There are times where I feel it's helping, and times when it really isn't. (My main symptoms are constipation and bloating) It might be that FODMAPs aren't the problem, or perhaps I'm still eating something that I shouldn't - when I saw this post, I wondered if buckwheat could be the problem, or one of them.

    The Monash app lists buckwheat kernals 1/8 cup serving ok, but 1/4 serving as having moderate amounts of Oligos-fructans. Under buckwheat groats, it says 1/2 cup and 3/4 cup are both fine...

    What's the difference between kernals and groats?? When I've looked up the difference online it says that kernals contain an inedible outer layer, so no-one should be eating those anyway?

    I live in the UK and have been eating Organic unroasted buckwheat from Wholefoods, buckwheat flakes and also buckwheat flour.

    Any further info would be gratefully received!

    • Alana Scott 15/04/2016 9:40pm (19 months ago)

      Hi Liz,

      I've contacted Monash and I am just waiting on some more information about the difference between the buckwheat groats and buckwheat kernals, so I will update you when I find out more. At this stage it looks like only USA buckwheat groats are low FODMAP. So the buckwheat kernals/groats from the UK could possibly be an issue. It might be worth removing the buckwheat groats and buckwheat flakes (untested) for a couple of weeks and see if that makes a difference. Buckwheat flour is low FODMAP so you can leave that in your diet (the manufacturing process changes the FODMAP content).

      Also keep in mind that the low FODMAP diet is good for constipation and bloating but sometimes you will need to combine it with other strategies to resolve your symptoms. Often a symptom management plan would consider increasing fibre intake, daily exercise, water intake, toileting posture, a magnesium supplement, probiotics, checking for dyssynergic defecation, and sometimes a low dose of medication. If you haven’t already, then I would consider discussing some of these with your doctor and dietitian.

      Sometimes the reintroduction phase can help provide constipation relief by helping you find your happy balance. This is because you might find a few high FODMAP foods act as a slight laxative but don't give you strong symptoms.

      I hope this helps answer your questions and I will let you know when I have more information about buckwheat!


  • Camilla 18/04/2016 4:39pm (19 months ago)

    Hello and thank you for a very useful website! I'm currently done with 6 weeks of elimination (VERY successful), and just finished "lactose-week" yesterday. I didn't get any major symptoms, discomfort, bloating etc., but I somehow felt like my stomach got a just a bit "bubbly" about 10-20 minutes after eating the yoghurt. I really want to test lactose again (since "bubblyness" could be a coincidence) but not sure if I should wait until I'm done testing all the other food groups (in 7 weeks), or I should "restart" lactose again in a couple of days? Camilla, Norway

    • Alana Scott 19/04/2016 5:40am (19 months ago)

      Hi Camilla,
      I'm so excited to hear that your FODMAP re-challenges are going well! Okay so it's up to you whether or not you want to retest lactose again now, or once you have finished the other groups. The schedule is just a rough guideline and the order you test the FODMAP groups in really doesn't matter. This means if you really want to re-test lactose straight away, then you can start the test again after your three day washout period.

      It sounds like you aren't getting any major symptoms anyway, which means you should be able to reintroduce small amounts of lactose back into your diet anyway (a little bit of gas and a small amount of bloating (mild symptoms) is really normal).

      I hope that helps. Well done on working through the reintroduction phase!


  • Leah 20/04/2016 7:45pm (19 months ago)

    I tested galactans (mostly eating butter peas and almonds) on a Saturday and Sunday. I felt really bloated but didn't have any other problem until the following Saturday when I had a really bad episode and had so much gas pain I could barely walk. Could this be because of the test from the previous weekend? Or maybe stress or some other unknown? I had been feeling so good for weeks and I just can't figure out what caused it. Thank you for your wonderful website!

    • Alana Scott 20/04/2016 9:18pm (19 months ago)

      Hi Leah,

      I'm sorry to hear you are had a horrible reaction! FODMAP reactions normally occur within a 2 to 3 day period after eating the food (this is why a 3 day washout period is used between FODMAP re-challenges). This means your reaction a week later is unlikely to be related to your galactans test. So my guess is that there is another factor or factors that triggered your symptoms. I would recommend you go back on the elimination diet for a few days until your symptoms settle and then continue on with your re-challenge tests. Sometimes our bodies are a mystery! I hope that helps.


1 2 3

RSS feed for comments on this page | RSS feed for all comments