Reintroducing FODMAPs

The reintroduction phase of the low FODMAP diet is arguably the most important part of the low FODMAP process. Done correctly, when you reintroduce FODMAPs, you will start to get some answers around your Irritable Bowel Syndrome dietary triggers.

Why Do We Need To Reintroduce FODMAPs?

While the avoidance of FODMAPs can help reduce gas production and loose stools, FODMAPs also have some benefits for the gut (1). FODMAPs are, in fact, prebiotics which means that they provide a good environment for good gut bacteria to thrive in.

Even over the short period of the FODMAP restriction phase, avoiding FODMAPs can reduce certain good gut bacteria by around 50% (2). Although this is likely to be safe in the short term, especially when balanced with the need to find a trigger for IBS symptoms, it is not an ideal long-term diet to follow.

Not only this, but following a low FODMAP diet in the long term can unnecessarily restrict your diet and may prevent you from enjoying social occasions and could cause nutritional deficiencies (3).

How Does It Work?

There are 10 FODMAP reintroductions to cover – Oligosaccharides (1 x cereal and 1 x wheat), Fructan vegetables (onions, garlic and leeks), Polyols (1 x Sorbitol and 1 x Mannitol), Galacto-oligosaccharides, Fructose and Lactose (4).

Each reintroduction is done over a period of 3 days, increasing the amount as you go. At the end of the 3 day period, you will need to have a 3 day ‘washout’ period before starting on your next trial. This is to ensure that all FODMAPs are out of your system.

This process will take around 9-10 weeks in total. This phase may be even longer if you have social events where you would prefer to take a break from possible FODMAP reactions.

What If I have a Reaction?

If you have any symptoms then you need to stop that reintroduction, wait 3 days for a ‘wash out’ period and then continue on to your next reintroduction.

What To Reintroduce First

There are no official ‘rules’ about which FODMAP group should be reintroduced first but the most common FODMAP intolerances that I see in practise tend to be fructans, so I advise to leave these till the end.

This may be disappointing as pasta, garlic, onion and wheat products are often what people miss the most. However, having a reaction on your first reintroduction may reduce your motivation to continue with this process.

What Foods To Use

One thing you need to be careful with is that you use foods which contains 1 FODMAP for your reintroduction otherwise you will be confused as to what is causing any reactions.

Foods which contain more than 1 FODMAP can be reintroduced at a later date and your dietitian can talk you through this.

How Much?

As the reintroduction of FODMAPs is looking at intolerances and not allergies, even if a FODMAP causes you problems then you will still be able to tolerate a small amount. This is why the reintroduction is done over a 3 days period, each day slowly increasing the amount of FODMAP you consume.

Examples of appropriate amounts to start with would be 125 mls of milk or 1 teaspoon of honey.

However, your dietitian may need to specifically tailor amounts to you to make it more appropriate (5). For instance, finding out that you can tolerate 2 slices of bread/day may not be very useful for a young man who would normally have several slices.

What If I React To Everything?

If you find yourself reacting to everything then don’t fret. There may be a simple explanation;

How big are your portions?

Fructans and Galactans will cause symptoms even in those without IBS, when eaten in large enough quantities (6). So try the reintroduction again, but this time in 1/2 the portions you previously trialled.

Were you following a low FODMAP diet?

FODMAPs can have an accumulative affect and so if you have other FODMAPs in your diet during a trial then this may cause a reaction which is only partly caused by your tester FODMAP.

What else was going on?

Remember, stress can play a huge role in digestive problems. If this is the case, then think about reintroducing FODMAPs again when you are experiencing less stress.

What else did you eat/drink?

Caffeine, fatty foods, resistance starch, fibre, alcohol, meal size and spices can all play a role in digestive problems (7).

Can I Do This Alone?

The reintroduction phase of the low FODMAP diet is quite complex and you will need support throughout. It is strongly advised that you do not try this without the supervision of a dietitian who will be able to guide you on portion sizes, symptoms and timings.

How Do I Get Help?

If you would like further help with the reintroduction phase, please contact me on the form below and I can book you for a 15 minute free phone call to run through the service that I provide and any questions you may have.

Hard Copy References

1. London: Department of Gastroenterology & Department of Nutrition & Dietetics Guy’s & St Thomas’ NHS Foundation Trust London UK, February 2017. Print.

Last updated on March 6th, 2021 at 05:45 am