There are a few ways to tackle the reintroduction phase, and it can be quite a long, complex process. Your dietitian is the best person to advise you on which method will be best for you and can also help you to make sense of the results of your challenges.
The Monash FODMAP app also contains a detailed reintroduction guide, which can be found in the diary section of the app. It includes a step-by-step workflow showing which foods and quantities to test for each of the FODMAP types on every day of the challenge. Once you select your challenge, it is added to the diary section of the app so that you can track your progress and findings through the challenge.
Whilst this feature is handy to have in your pocket, comprehensive and easy to follow, it is still intended to be used under guidance from a registered dietitian. It is not personally tailored to your nutritional and medical needs and does not replace the knowledge and input of your professional care team.
The most important part of the reintroduction phase is choosing the right food to use for your FODMAP challenges. This is why you're advised to only choose from the recommended foods that contain one FODMAP type. This way, you can be sure exactly which FODMAP you're challenging in isolation.
For example, mango contains only excess fructose, so it's a good choice for a fructose challenge food. In contrast, watermelon, at higher portion sizes, contains fructose, mannitol and fructans. This makes it a bad choice for challenging your maximum fructose tolerance. When using food such as watermelon, which contains multiple FODMAPs, you may react to the presence of the other FODMAPs. This risks skewing the test and confusing your tolerance to fructose with your reaction to the other combined FODMAPs. [1]
What if I don't like a suggested challenge food?
If you don't like the recommended challenge food, you can choose any food from the same FODMAP category. Double-check the Monash FODMAP app to ensure it contains only that specific FODMAP type.
Ideally, you'll challenge foods you enjoy and eat often and at a full serving size. There is no need to challenge foods you don't readily eat. The exception to this is if you eat them 'hidden' in things like takeaways, ready meals or sauces. For example, if you don't usually cook or eat whole garlic cloves at home, you may think it makes sense to skip this challenge. However, if you often eat out or have foods containing garlic powder, garlic salt, garlic granules or flavourings, then you should still challenge garlic.
Remember, the point of your challenges is to see which foods you can reintroduce back into your diet as part of your regular recipes and eating habits. Although you may likely need to make changes to your diet, portions and preparation techniques. Overall, the idea is to establish a new normal and build from there in a way that's easy and realistic for you. [2]
Low FODMAP Challenge Food
My biggest tip for following the low FODMAP diet is to invest in a pair of kitchen scales. (Affiliate link). This especially applies during the reintroduction phase. If an extra ¼ of a portion makes the difference between tolerating a particular FODMAP or not, I want to know I'm being as accurate as possible.
It's also a good idea to reintroduce challenge foods in the way you would typically eat them. If you only ever eat cooked onions, then make sure to cook them for your challenge meal rather than eat them raw.
Important Update to Reintroduction Foods 2025
The reintroduction phase has had a significant update in the Monash FODMAP app in April 2025. Based on the latest research and test results, some of the foods previously recommended to use as reintroduction challenge foods have been swapped or changed. Whilst new challenge foods have been added, some of the previous foods remain.
While this contradictory information can seem confusing, the basic explanation is that the FODMAP results can and do change over time. This is one of the reasons why it's important to continue retesting your tolerance to foods and FODMAPs over time.
I have updated the list below to reflect the current advice. You can visit the official Monash FODMAP blog post for a more detailed explanation and to view tables of the previous recommendations versus the updated foods.
This recent update follows previous changes to the portion sizes and cut-off values for fructose-containing vegetables in the Monash FODMAP app. If you're not familiar with how that update affects the recommended portion sizes, then it's worth reading the official explanation here.
To give you an idea, these are just some of the updated foods and portions you could use for your challenges. This is not an exhaustive list. Please refer to your dietitian and the Monash FODMAP app for more options and possible substitutions:
GOS Challenge Food and Portions
Silken tofu:
- Day 1 = 46 g
- Day 2 = 90 g
- Day 3 = 130 g
Pinto beans (canned, rinsed and drained):
- Day 1 = 65 g
- Day 2 = 80 g
- Day 3 = 100 g
Another suggested option for your GOS challenge is canned and rinsed adzuki beans. Previously, almonds, canned chickpeas and green peas were suggested. After retesting, these were found to also contain fructans, so they are no longer recommended for testing your tolerance to GOS.
Sorbitol Challenge Food and Portions
Apricot (fresh):
- Day 1 = 70 g
- Day 2 = 102 g
- Day 3 = 125 g
Cherries (frozen):
- Day 1 = 13 g
- Day 2 = 16 g
- Day 3 = 19 g
Other options for the sorbitol reintroduction challenge include fresh cherries. Whilst fresh cherries have larger test serving sizes, these are fairly seasonal. I chose to list frozen cherries, which are more readily available year-round. Previously, avocado was a popular option for this challenge. After retesting, avocado was found to contain a different polyol called perseitol, so it is no longer recommended for testing your tolerance to sorbitol.
Mannitol Challenge Food and Portions
Celery (stalks):
- Day 1 = 75 g
- Day 2 = 95 g
- Day 3 = 112 g
Mushroom (portobello variety):
- Day 1 = 14 g
- Day 2 = 75 g
- Day 3 = 112 g
As an alternative option for this challenge, you can try sauerkraut made from white cabbage. Previously, cauliflower and sweet potato were recommended. After retesting, both are now listed as low FODMAP foods containing fructans.
Fructose Challenge Food and Portions
Asparagus:
- Day 1 = 57 g
- Day 2 = 85 g
- Day 3 = 100 g
Mango (all varieties, fresh):
- Day 1 = 9 g
- Day 2 = 20 g
- Day 3 = 30 g
Another suggestion for your fructose challenge is orange juice. Whilst asparagus and mango were both original options for testing fructose, the recommended challenge portion sizes have been changed. Mango portions are now significantly smaller, whilst the asparagus portions are much larger. Sugar snap peas have been removed as they are now listed as fructan-containing.
Fructans in Grains Challenge Food and Portions
Couscous (wheat-based, cooked weight):
- Day 1 = 75 g
- Day 2 = 100 g
- Day 3 = 157 g
Pasta (wheat-based, cooked weight):
- Day 1 = 80 g
- Day 2 = 100 g
- Day 3 = 155 g
You can also challenge wheat-based puff pastry as an alternative to one of the suggestions above. It's worth noting that the recommended challenge portions each day for pasta have been reduced. Previously, white, wheat bread was recommended. As retesting has shown that there are too many variations in white bread between different countries, you are now recommended to test the type of bread, local to you, as a standalone challenge.
Fructans in Fruit & Vegetables Challenge Food and Portions
Banana (common, ripe):
- Day 1 = 47 g
- Day 2 = 72 g
- Day 3 = 95 g
Leek (white bulb only, raw weight):
- Day 1 = 15 g
- Day 2 = 30 g
- Day 3 = 45 g
These are now the only suggestions for your fructans in fruits and vegetables challenge. Beetroot and Brussels sprouts have been removed from the challenge as retesting shows they do not contain enough fructans in typical portion sizes. Grapefruit and raisins have also been removed as they are now listed as fructose-containing.
Fructan Onion Challenge Food and Portions
Onion (red or white):
- Day 1 = 13 g
- Day 2 = 17 g
- Day 3 = 22 g
Onion remains an isolated fructan challenge with only a slight decrease in the recommended challenge portions.
Fructan Garlic Challenge Food and Portions
Garlic clove:
- Day 1 = 1 g (⅓ clove)
- Day 2 = 2 g (⅔ clove)
- Day 3 = 3 g (1 clove)
No change to the garlic, standalone fructan challenge.
Lactose Challenge Food and Portions
This challenge does not apply to vegans as we do not consume lactose. I include these options for vegetarians and non-vegans.
Milk (cow's milk, regular or reduced fat):
- Day 1 = 63 ml (¼ cup)
- Day 2 = 130 ml (½ cup)
- Day 3 = 250 ml (1 cup)
Yoghurt (Greek, regular fat):
- Day 1 = 62 g
- Day 2 = 125 g
- Day 3 = 200 g
The yoghurt challenge now specifies Greek yoghurt rather than plain. Custard and ricotta cheese have been removed after retesting shows they do not contain lactose in high enough quantities at typical portion sizes.
This list is not exhaustive. It is provided for reference only and does not replace the knowledge and guidance of a FODMAP trained dietitian. As the recent updates show, reintroduction foods and quantities may change over time as more is learned about the FODMAPs in food.
Do I need to challenge all of these foods?
It's important to remember you're challenging the FODMAPs and not the food. This means that you don't need to individually reintroduce every single food you eliminated. Generally, if you react to one food containing a certain FODMAP, you'll likely react to all foods containing the same FODMAP type.
For most of the challenges, you only need to eat one food from that FODMAP category. However, because the fructans in various foods affect people differently, the fructan category is broken down further into specific food types. [3] You should challenge every fructan type that you eat as a separate challenge. The amount of fructans in different food types varies widely. Some people find they can tolerate the fructans in one food type but not another. [4]
Which foods did you use for your FODMAP challenges? How did it go for you? Let us know in the comments below.
References
[1] Efficacy and Findings of a Blinded Randomized Reintroduction Phase for the Low FODMAP Diet in Irritable Bowel SyndromeVan den Houte, Karen et al.Gastroenterology, Volume 167, Issue 2, 333 - 342. https://www.gastrojournal.org/article/S0016-5085(24)00170-7/fulltext
[2] Reintroduction using the diary function via Monash FODMAP blog: https://www.monashfodmap.com/blog/reintroduction-using-diary-function/ Accessed 17/04/2025
[3] Fructans and FODMAP reintroduction via Monash FODMAP blog: https://www.monashfodmap.com/blog/fructans-fodmap-reintroduction/ Accessed 17/04/2025
[4] Fructan and Fructooligosaccharide general information and food table via Food Intolerances Org: https://foodintolerances.org/en/food-dictionary/fructan-and-fructooligosaccharide-content-of-food Accessed 17/04/2025
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