Food Blog

Our latest articles on food allergies & intolerances, low FODMAP diet, free-from recipes, health & wellness, dietitian blogs, reviews & lots more...

Reintroducing FODMAPs

Reintroducing FODMAPs

by FoodMaestro | 10 October 2016

The difficulties in accessing current and reliable information on Reintroducing FODMAPs.

Authored by Lee Martin MSc RD

The low FODMAP diet can be looked upon as a diagnostic tool to identify which FODMAPs and portion sizes can be consumed before triggering symptoms. The reintroduction phase is an integral part of this process helping to discover your own personal tolerance levels. The main focus of long term treatment to control IBS symptoms is the emerging evidence of what is being termed a ‘modified low FODMAP diet’. This diet contains high FODMAP foods but still maintains control of symptoms while allowing the diet to be more varied than a restricted low FODMAP diet. Eating a tolerable amount of high FODMAP food means you are obtaining the beneficial effects of FODMAPs i.e. prebiotics, fibre and other nutrients without the negative effects of IBS symptoms. It also helps ensure you have a good food related quality of life i.e. you do not look at food in a negative way, as often people following a long term restricted diet do. Of course expanding the diet to include high FODMAP foods also means that when eating out, socialising or travelling you are not so restricted in your meal options. It is even possible to travel the world on a modified low FODMAP diet (see here) but none of this can be achieved without completing the reintroduction phase.

The first research paper to discuss the low FODMAP diet was published exactly a decade ago (2006). Since then the information available for following the restriction (or elimination) phase of the low FODMAP diet has increased exponentially, as has the popularity of the diet in the media and public domain. Ten years ago you would have found it very difficult to find information on a low FODMAP diet but now if you type ‘low FODMAP diet’ into Google you get nearly 600,000 hits. Google ‘reintroducing FODMAPs’ however and you only get just over 44,000 hits (September 2016). The image below shows how the Google search terms for FODMAPs has exploded in the last few years.

This is important as many people with IBS will search the internet for information on IBS. Both UK clinical guidelines and research publications recommend that people with IBS see a dietitian to help implement the low FODMAP diet, however many people will not. This could be for a variety of reasons including lack of access to a trained or knowledgeable ‘FODMAP dietitian’, there being no dietetic service available in local areas or in some cases referral to a dietitian may be refused by medical professionals. This last point is becoming a common occurrence in the UK and I have written about before (see here).

The low FODMAP diet is actually a three phase diet consisting of; 1. a short (2-6 weeks) period of restricting FODMAPs (termed the low FODMAP restriction diet) followed by 2. a longer (at least 6-10 weeks) period of reintroducing FODMAPs to personal tolerance termed the Reintroduction phase.  Finally, 3. a long term maintenance phase where you self-manage your IBS often by following a modified low FODMAP diet. For more background on the three phases of the low FODMAP diet and a ‘modified low FODMAP diet’ then have a read of this article.

If you have IBS and can see a dietitian experienced in providing low FODMAP dietary advice, then the research shows this will deliver the best efficacy for this treatment approach.  What if your dietitian is not trained in delivering the low FODMAP diet? Or what if you simply cannot access (or do not want to access) a dietitian? Should you be denied access to valuable information that could improve your IBS symptoms that only a dietitian can provide? Of course not, which is why most people in this situation will turn to Google as highlighted above. The problem with this is there is still some inaccurate information on reintroducing FODMAPs and as there is also less information on reintroducing FODMAPs on the internet you are more likely to come across some misinformation. Unfortunately, some of this misinformation actually comes from some high profile and influential sources.


Inaccurate information on Reintroducing FODMAPs

There has been a couple of new internet sites devoted to the low FODMAP diet recently both aimed at the public rather than health professionals. They come from the collaboration of Nestle Health Science, University of Michigan and Cedars-Sinal. Nestle has produced ‘LowFODMAP Central’ ( and Michigan has produced My GI Nutrition (  Both sites provide some great information on the low FODMAP diet but there are a couple of inaccuracies and contradictions in the advice they provide on reintroducing which can affect the accuracy of the results you obtain when reintroducing high FODMAP foods.

On the Michigan GI Nutrition site, the video produced on reintroducing (found here) correctly suggest you only ‘Test with foods that contain one type of FODMAP’.  They go on to say this is important because if you test a food that contains multiple FODMAPs and you experience symptoms how will you know what FODMAP triggered your symptoms? Unfortunately, in their example for testing the polyol ‘mannitol’ they suggest using ½ a cup (37g) of mushrooms. Mushrooms however contain both mannitol and fructans at 1 cup (74g) (Source: Monash University Low FODMAP app). When you test FODMAPs it is recommended to gradually increase the portion size you consume over three days i.e. ½ cup, 1 cup to 1½ cups. If you experience symptoms from eating a larger portion size of mushrooms it could be the fructans rather than the mannitol, or a combination of the two that trigger symptoms. This can lead to inaccurate results and potentially avoiding foods containing mannitol when this is unnecessary. They also provide a handout (found here) which advises nectarines or apricots as a test for the polyol ‘sorbitol’, however both of these fruits contain a moderate or high amount of fructans respectively at the portion sizes suggested for testing (Source: Monash University Low FODMAP app).

There is also a slight confusion over portion sizes of fructans when challenging garlic. The video suggests starting with one clove of garlic however even half a clove of garlic is high in fructans (Source: Monash University Low FODMAP app) and eating 1 whole garlic clove is more likely to trigger symptoms. Better to start with ¼ a clove of garlic and increase to ½ and 1 whole clove on the final day of testing to obtain more accurate results from any symptoms experienced.       

Why is there contradictory information on reintroducing FODMAPs?

So why do we have a situation where there is some inaccurate information and discrepancies in information on the same website being provided to help those with IBS?

The examples provided above along with other sources you will find on the internet often borrow the information on reintroducing from a Monash University paper published in 2012 (available here). It is a really good paper and well worth a read and it is still the only scientific article to date that has published an example of foods to use when reintroducing FODMAPs along with portion sizes. The problem is the information is now out of date due to updated information on the FODMAP content of foods that shows some of the previously recommended foods (i.e. mushrooms and apricots) actually contain more than one type of FODMAP. In addition, there is also a general consensus about the protocol for reintroducing which includes the importance of using foods than only contain one type of FODMAP and gradually increasing the portion size of the FODMAP being challenged over 3 days. Whereas previously the same portion size of FODMAP food was suggested for each of the 3 day challenges.   

Very recent research papers (see here and here) have been published which have focused more on the reintroduction phase and hopefully soon a paper that describes the most up to date and general consensus on a reintroducing protocol will be published. This would be useful to help prevent the inaccuracies and contradictory information found on many websites and advice provided by dietitians who rely on this information too. This is particularly important for dietitians in America where unlike the UK there is no ‘official’ training provided on the low FODMAP diet and dietitians have to rely on the research and literature available. Until more research and fully accurate literature is freely available there are a couple of resources you can rely upon.  

What are your reliable Reintroducing FODMAPs resource options?

Up until very recently the best source of information for reintroducing FODMAPs was only available to registered dietitians. King’s College London (KCL) University pioneered their highly respected low FODMAP training courses for dietitians in 2010. In addition, they produced an information booklet on the application of the low FODMAP diet restriction diet and another booklet on how to complete the reintroduction phase. These excellent resources aid dietitians in providing up to date and accurate information on how to implement the entire low FODMAP diet and provide patients with clear information to support their treatment. As mentioned these resources were only available to purchase by registered dietitians…. until now.  

The KCL FODMAP research team have collaborated with FoodMeastro and produced an app which provides this information only dietitians previously had access to and have made it available to the public for purchase. The ‘FODMAP by FM’ app is recommended to be used in conjunction with a dietitian which is strongly advised. The app helps the patient record their progress through the diet facilitating an easy two-way communication between patient and dietitian. The app provides clear and basic instructions for reintroducing FODMAPs and records your symptoms to help the user obtain as accurate results as possible.

If you prefer a book and/or require additional information and support you can also purchase the first ever book dedicated to reintroduction: ‘Re-challenging and Reintroducing FODMAPs’ (available on Amazon here). I recently wrote and published this self-help guide as I have a particular interest in this phase of the low FODMAP diet and have frequently been told of the struggles people were having reintroducing, especially without access to a trained dietitian. There are plenty of books that discuss the low FODMAP restriction diet but none that dealt with the complexities of the reintroduction phase. As with the ‘FODMAP by FM’ app, this is best used in conjunction with a dietitian who can personalise the advice provided in the book, however it can be used alone if there is no option of dietitian support. If you require more information on the reintroduction phase of the low FODMAP diet, please visit

About Lee

Lee Martin is a King’s College London FODMAP trained registered dietitian in the UK. In 2014 Lee took up an academic role at King’s College London working within the FODMAPs team. He left his research role to travel the world for a year and blogged about his experience. Now back in the UK Lee has a new role at University College London Hospital as a Specialist Gastroenterology Dietitian.  With a particular interest in the FODMAP reintroduction phase Lee has written a best practice guide that walks you through the re-challenging and reintroduction process. You can follow Lee via his website or on Twitter.