Ep.18 Mastering FODMAP reintroduction – IBS Podcast
11 Oct, 2023

Episode Intro

How to reintroduce foods back into your diet after you've done the elimination diet. If you haven't heard the overview, go back and listen to Ep 17 where I explain what the FODMAP diet is, who it's for and who shouldn't use it. Today, we're talking about how to bring things back in again if you start to feel better after taking the foods out of your diet. And I'm going to talk about how to do it bit by bit, and also what happens if you do get a reaction. What should you learn from that? And how can you build out your long term diet that hopefully minimizes your symptoms


Podcast transcript

Welcome to episode 18. This is The Inside Knowledge with me, Anna Mapson.

The reintroduction phase of the low FODMAP diet is something most people, I find, don’t get round to. They eliminate foods from their diet. And then actually bringing them back in again feels too scary and too overwhelming.

What happens is you either stay on a low FODMAP diet. Or you don’t know if you’ve got any benefit from the diet so gradually bring things back in without really checking whether they are making a difference or not.

How to approach the reintroduction phase of the FODMAP diet

The aims of reintroducing the foods is to try to get your confidence up. So try to make you feel more confident about eating these foods.

And we do it in a really slow, measured, and careful way. It’s about helping you identify triggers, and ultimately getting you to the place where you can eat a broad range of foods again without being so restrictive.

Stage 2 of the FODMAP diet – reintroduction

So if you’ve done a FODMAP diet, you’re feeling better and you’re ready to move to the next stage, this is how you’re going to get started.

Pick one of the FODMAPs at a time and bring them back into your diet, gradually increasing the amount you eat over three days.

Each of these challenges needs to be chosen quite carefully so that you’re only picking one type of FODMAP at a time. This is where it is really helpful to understand which foods are in which FODMAP grouping.

As I said, before. It’s not really an intuitive diet, so you wouldn’t necessarily think that perhaps broad beans or avocado might be high FODMAP foods. This means that if you’re picking a food that’s got two types of FODMAPs, like apples, for example, or cashew nuts. Then you introduce those without testing the individual FODMAPs first you won’t necessarily know which one you’re reacting to.

So this is why planning it out is really helpful.

How to select your first reintroduction

The first thing to do is to pick which of the FODMAPs you’re going to bring back in. There isn’t really a right or wrong order to bring them back in.

I do have a chat with my clients about ‘Which foods maybe that you’ve missed the most? Like, what are you craving? Maybe things that would help you expand your diet the most’.

So for people who cook for others, sometimes it’s things like pasta and that would really help you with family meal times. Other times it might be onions and garlic because you enjoy eating out. It’s very hard to avoid onions and garlic when you’re eating in restaurants or pubs or something.

It doesn’t really matter how you’re going to select the food, what matters is that you select one of them, and there are lots of these to work through.

There are 11 stages of the low FODMAP reintroductions, and sometimes you need a little bit longer in between each one. So three days for each FODMAP plus one washout day at least.

Taking a break between reintroductions – the washout day

And what I mean by a washout day is a day where you go back to the low FODMAP diet and just reset yourself. So you, you do three days of reintroduction, increasing the amounts. If you feel okay, you still have a day off.

Go back to low FODMAP for one day.

If you had a reaction to the food, then you need to take a bit longer, maybe three or four days, to reset your gut, to re calm yourself down, and make sure that you haven’t got any symptoms before you start introducing them.

How long does the FODMAP reintroduction process take?

People often ask, how long is this gonna take? And… The minimum amount of time is normally about six to seven weeks, and that is because you have three days for each FODMAP plus one extra day, which adds up to four days per FODMAP.

And there’s 11 groups. So you could do 44 days. However, some of them you might be a little bit more relaxed about, and I can explain that.

Foods spanning two FODMAP groups

So when you’ve got a category where with two FODMAPs in, if you’ve sailed through the Galacto-oligosaccharides, the GOS, and the fructans, for example. When you put them together,

You probably don’t need to go through the full thing to the full extent if you’re in a rush. So the official line is that you take this amount of time. Which could take you somewhere around 10 weeks.

So this can feel like a long, long road if you’ve already been struggling on the low FODMAP diet. Because as you’re going to be expanding your diet, which is great, you still may feel some level of restriction.

Step by step reintroduction process for FODMAPs

So let’s think about how to actually bring the foods back in again. I’m going to give an example from the FODMAP grouping of polyols and particularly mannitol.

This includes things like mushrooms and cauliflower, and large amounts of sweet potato, celery, that kind of thing. What I suggest you do is just pick one food from a FODMAP group and just stick with that. That is the easiest way because you’re retesting the same foods.

Can you select multiple foods from the chosen FODMAP group?

There is a way that you could mix it up a bit by selecting foods out of that entire FODMAP grouping, and that’s also a valid approach.

But it’s kind of easier if you just stick to the same food.

  1. So for example, with mushrooms, on the first day you just put one to two mushrooms on your plate, which is around 10 grams.
  2. Then on the second day, assuming you feel fine, you’re going to increase that up to sort of a Three quarters of a cup or somewhere in the right rounds of 40 grams and
  3. Then on the final day you want to get to 80 grams with most fruit and vegetables you want to aim to get to around 80 grams of the food because that is one portion. Or, what you would normally eat in a meal.
What about bigger fruits?

For example, like with grapefruit, they are so big and juicy that actually 80 grams is quite small and quite a small piece of the fruit. So, often a grapefruit could be somewhere like 200 grams. So, one grapefruit might be what you would eat in one sitting. Therefore, you want to get up to one fruit, not 80 grams.

Eating multiple foods in the group

But, if you’re going to vary it, maybe you do,

  1. on the first day, you do a few mushrooms.
  2. The second day, you might do, like, one cup of sweet potato, which would be somewhere like, 180 grams,
  3. and then you might go back on the third day to 80 grams of mushrooms.

In this way, you’re varying the food between mannitol portions, increasing the amount of mannitol within the three trial days.

It doesn’t really matter, but I find it easier if you do stick to the same foods and try to keep things a little bit consistent.

If the reintroduction trial goes well

If that goes well, you should then be okay with other foods in that food group. So assuming your mushroom challenge goes well, then you should be able to eat things like cauliflower, butternut squash, and celery, and fennel. Because those are also high in mannitol.

Other IBS triggers in foods

But it is always worth being aware that other components of food can be a trigger, not just FODMAPs. So maybe it has got a high histamine content. Has it got high salicylates? Is there a particular protein like casein in the milk, not lactose for example, that is your trigger?

So there are other things that, not just FODMAPs, that can be a problem.

If you have an issue with a FODMAP reintroduction

That’s why, if you do have an issue, it’s worth testing it again with a different fruit or vegetable from that category.

The sorts of symptoms that you are looking for are things like increases in your bloating, changes to your bowel habits. Maybe things like headaches and skin rashes, like any other symptoms that you would normally be checking and monitoring and thinking about.

Those are also valid, but critically we’re thinking about the digestive impact of eating these foods.

How to check for FODMAP reactions

I ask my clients to check their symptoms around eating the food.

  • How do they feel when they’ve just eaten it?
  • 3 to 4 hours later,
  • and then 12 hours later,
  • and then perhaps 24 hours later.

So I really want you to kind of keep on top of the symptoms whilst you’re doing this challenge. To make sure that you’re just thinking about when the symptoms come, if they come at all, and hopefully they won’t.

What else could be influencing the results?

It’s really important to be aware of other confounding factors, like, what else is going on at the time that you had this reaction.

Maybe you had a super stressful day at work. Or you didn’t get much sleep because your children were ill and you were up through the night. Or you went out for a meal and you had a glass of wine that you don’t normally do.

These things can all impact on your symptoms as well, so I want you to also measure. What confounding factors, like what else could have influenced the results because this is really important. The other thing to be aware of is like just picking a time to do the reintroduction when you’re not too busy.

When to do the reintroductions

So whilst I don’t want anyone to put it off for too long, like for example, two to four weeks on the low FODMAP diet is normally enough to know whether you’ve had improvements. Don’t put it off for ages. But at the same time, don’t also pick a time when you’re like moving house or about to go on holiday because it will be very difficult to know whether the reactions are something to do with that or something to do with your food challenges.

Don’t be over vigilant

Now whilst I’ve said keep on top of your symptoms and check them like every few hours, I also… Don’t want you to be hypervigilant, so anxiety can make things worse. This is where, right back in episode 2, when I talk about how to eat, and episode 4, where I talk about the gut brain connection and stress.

Techniques in there about mindful eating, chewing your food really well, slowing down. These really come into play when you are doing a food challenge. It’s so important to try to keep yourself feeling calm. Keep yourself just feeling like you’ve got this, you can do it, and try to calmly monitor your symptoms.

Some reaction can be normal

The other final thing to be, really be aware of is some gurgling is normal. It’s kind of normal to have some gas with some foods, like for example beans and pulses. So some level of reaction is okay and tolerable.

When to stop the FODMAP reintroduction trial

What you’re looking out for is when the symptoms become intolerable. When it is getting to the state where you don’t feel happy anymore. You feel pain, you feel too much gas. You’re running to the bathroom, any of those things, like that would be a sign to stop the trial.

Where possible, you want to try and get three days in so that you know how much of the certain food gave you the trigger to kick your symptoms off.

What level of exposure to that food is the point for you where your IBS comes back. That’s why it’s useful to have three days worth of data.

However, if you’re feeling terrible after day one and you just think, as soon as I ate that, I don’t know, asparagus, I felt terrible and I knew it was the asparagus. There was nothing else going on in my life that day. I felt really good and as soon as I ate that I felt bad. Okay, if that happens to you and you don’t want to go to day two, here’s what you can do.

Pause the challenge for now

So in my example, asparagus is high in fructose. So what I would do is park the fructose challenge for now. Say you’re not going to eat things that are high in fructose because of this reaction for now.

And what you’re going to do is work through the others.

Carry on going through the other FODMAP challenges.

Don’t worry about fructose for now. Then you’re towards the end or in another few weeks, we’re going to come back to it.

Trial the fructose challenge again with a different food. Maybe asparagus on their own are just an issue for you. So what you could do is pick something else, maybe like cherry tomatoes. Maybe pick mango or honey.

And again, try them in increasing amounts on different days. Then make sure that you are… tracking your symptoms.

Keeping the food diary

And this is why it’s helpful to write it down so that you can go back and see. Okay, how did I feel when I had one asparagus spear, which is the trigger point for high moderate FODMAPs. How did I feel when I ate that compared to the time I ate six cherry tomatoes?

Was it the same kind of reaction or was it different?

This is where you can get some data like it’s being your own detective and gathering as much information as you can.  About the types of foods that you’re eating and the types of symptoms that you’re getting. In order to know whether it’s a food particular trigger or was it something else in the way that you ate that meal that could have potentially triggered your reaction.

Food intolerances can change over time

It’s also key to note that you can change intolerances over time, and this is particularly for people who have SIBO, that small intestine bacterial overgrowth.

As you get rid of the bacteria in your small intestine that have overgrown, it’s normal for people to become more tolerant to more foods. So things that you potentially were intolerant to six months ago, you can change your reaction to.

So sometimes our bodies just lack the enzyme to break something down and just biologically don’t have the capacity to digest things particularly well. Sometimes it could be the case that actually you can digest it. It’s just that bacteria were interfering with that process. And as we start to improve your digestion overall, there is hope that you can eat more and more of these foods. Which is why it’s good to come back and retest these foods again.

Because it won’t mean that you have to avoid asparagus for life.

After the reintroduction challenge process

So once you’ve finished doing all of your reintroductions, then make a note of the things that you struggled with, that you didn’t get on well with, and then you can come back to them maybe in three months, six months, a year. It doesn’t matter. The key thing is to keep on testing them and not to avoid them for the rest of your life.

Using the correct FODMAP data

Now, as you increase the amounts of some foods, you will also be exposed to more than one type of FODMAP. So with my asparagus example, at a low level, fructose is the key FODMAP. But as we get to more, so you might have five spears of asparagus, then you are hitting the FODMAP tolerance levels for fructose and fructan.

So this is where it’s helpful to do the tests. individually first and the Monash University FODMAP app is really helpful because you can look it up and see if foods contain more than one FODMAP.

For my clients and anyone who enters the group gut reset or individually works with me, I have a handout which says foods by FODMAP.

I will tell you the amounts that you can eat and that is based off data from the Monash University.

What if I’m very nervous of FODMAPs?

If you are super sensitive, you can do the challenges on alternate days as well. So you could do day one, reintroduce just one or two mushrooms.

Then you have a day off back to the low FODMAP diet. Day two, increase the amount a little bit more. Have a day off. Day three, then you go to the full amount.

So if you want to do it a little bit slower, that’s also fine. Particularly if it helps you manage anxieties about how the symptoms may be reacting.

Or just if you find that you’re super sensitive to a certain food. If you have been Low FODMAP for years or maybe over six months, and you’re just really nervous about reintroducing the foods.

In summary of this episode

I hope some of these tips will give you a chance to see how it’s possible to restart reintroducing some foods. Remember the goal is always to eat as freely as possible and eat as broad a balanced diet as possible. Going through this period of restriction was just one tool that you could use. This is an intervention.

It’s not a way of life. If you’re not quite sure whether you’re ready to reintroduce foods or not, what you could do is potentially go back to a really strict low FODMAP diet for one to two weeks because to try and get on top of your symptoms.

What I find is that people say they’re on a low FODMAP diet and they’re still getting symptoms, so it kind of means that they’re not necessarily managing it particularly well.

Or, it’s not actually a FODMAP issue.

So, what would be really helpful is to first of all, go super strict low FODMAP for one to two weeks and then go through this reintroduction process.

Because what you might find is you’ve actually been avoiding foods for a long time that aren’t a problem. And potentially it’s just one or two foods out of a whole food group. And you’re cutting out a lot more than you need to.

Ask me your FODMAP reintroduction questions

I hope some of this has been helpful and if you have any questions do drop me a line. I’m going to do a live on Instagram so come over and watch that and I’ll go through some questions that I’ve had on the low FODMAP diet.

Otherwise I’ll leave it there for this week and catch you next week. Bye!




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