Is Soy Low or High FODMAP?

If you are on the low FODMAP diet, you will find soy confusing.

You will be thinking that soya milk is lactose free but then confused because some people say to avoid it.

You may also be thinking that you need to find gluten free Soya sauce, but this is not the case.

Having this confusion often leads to mistakes on the low FODMAP diet.

In this article I will cover different types of soy and explain to you whether they are low FODMAP or not AND why.

Soy Sauce

Soy sauce is made using a fermentation process.

During this process, FODMAPs are destroyed. This makes soy sauce safe if you are on the low FODMAP diet.

Please note, soy sauce still contains gluten. This means that if you are coeliac or have a wheat allergy then you must opt for a gluten free soy sauce.

Soy Milk

Despite being lactose free, soya milk can be high in FODMAPs.

Soya milk is made from soy beans and so still contains too much GOS (1). This leads to IBS symptoms.

There is 1 way you could include soy milk into a low FODMAP diet. This is if it is made with just soy protein.

Soy protein contains no FODMAPs and so is low in FODMAPs.

Soya Beans

Soy beans are high in both GOS and fructans (Monash).

You must avoid soya beans if you are on the low FODMAP diet.

Soy Flour

This is made directly from grinding down soy beans. It is therefore high FODMAP and you should avoid it.

Tempeh

Tempeh is made with soy beans, so you may think it is high FODMAP.

However, it is low FODMAP. This is due to the process in which is has been made. In this process, soy beans are firstly soaked (reducing FODMAP content).

The soaked soy beans and then fermented using bacteria. Again, this process reduces the FODMAP content (2).

Tofu

You can enjoy tofu on a low FODMAP diet. BUT only the firm type!

Tofu is made by pressing soy beans. The longer this process takes, the less water there is in the tofu.

This process reduces the FODMAP content.

Edamame

It may surprise you to find that edamame beans contain less FODMAPs than soy beans despite being pretty much the same thing.

You can enjoy Edamame beans at a low FODMAP portion of 90g (1).

The reason that Edamame beans are low FODMAP is because they are harvested at a much younger age.

Summary

You can have soy in your low FODMAP diet. But, the type and amount is important. How soy is processed will determine how much FODMAPs it contains.

As with other foods, it is also important to check portion sizes.

References

1. https://www.monashfodmap.com/ibs-central/i-have-ibs/get-the-app/
2. https://www.bbcgoodfood.com/howto/guide/health-benefits-tempeh