My Guide to Choosing Soy Foods on a Low FODMAP Diet

Published on: 05/27/2024

Soy foods can be an important source of protein, fiber, and other nutrients, especially for vegetarians and vegans. But can soy foods be part of a low FODMAP diet? Let’s find out.

Is Soy Low FODMAP?

Soybeans do contain FODMAPs (galacto-oligosaccharides (GOS) and some fructans). However, not all soy foods are significant sources of FODMAPs. What makes a soy product suitable for a low FODMAP diet depends on three factors:

  • how it is processed
  • whether it is fermented
  • how much fiber it contains

Soy Processing and FODMAPs

GOS and fructans are soluble in water. When processing soybeans, if the final product retains the water, it is high in FODMAPs. But if the water is strained, the soy product becomes low in FODMAPs.

For example, soy milk from whole soybeans is made by grinding the beans and water together. Therefore, it’s considered high in FODMAPs. The same is true for soy yogurt, which is made from soy milk. Incidentally, when soy milk is made from soy protein (instead of whole soybeans), it is low in FODMAPs. It is popular in Australia but in the US, soy milk is usually made from soybeans.

On the other hand, any technique that involves soaking the soybeans in water and straining them will allow the FODMAPs to leach into the water and considerably lower the FODMAP content of that food. This is the case with firm tofu. During the preparation of silken tofu, the tofu retains the water and all the FODMAPs. 

Fermentation Can Lower the FODMAPs in Soy

Tempeh is made from the fermentation of cooked soybeans, which reduces their FODMAP content to a low FODMAP threshold. Some tempeh varieties also have grains like rice or millet but most are wheat-free. Others, however, may include barley, a high-FODMAP grain. Miso and soy sauce are other low FODMAP, fermented soy products.

Soy and Fiber

Finally, we need to remember that GOS and fructans are fibers. Hence, lower-fiber soy products are also lower in FODMAPs. For example, edamame, immature soybeans, are low FODMAP in moderate amounts.

Soy Food Derivatives

More are more soy products are appearing on our supermarket shelves. It can be hard to tell whether they may be suitable for a low FODMAP diet. Moreover, some may also contain other high-FODMAP ingredients, such as garlic or onions.

Soy burgers or meat substitutes have not been tested but most are likely to be high in FODMAPs as they may contain the fibers from soybeans.

Textured soy protein, the main ingredient in many soy-based meat substitutes, is high in FODMAPs. 

Soy protein powder may be low in FODMAPs depending on the processing. Until we have more testing, its FODMAP status is unknown.

Soy lecithin and soybean oil are not a source of FODMAPs and are ok.

Soy flour is high in FODMAPs.

How to Choose Soy Foods on a Low FODMAP Diet

You can include many soy products in a low FODMAP diet. Use this guide to navigate the soy aisle, and don’t be afraid to experiment with soy foods. 

Low FODMAP Soy Foods

  • Tofu (firm or extra firm)
  • Plain Tempeh (no barley or other high FODMAP ingredients)
  • Edamame
  • Soybean oil
  • Soy sauce
  • Miso

High FODMAP Soy Foods

  • Soybeans
  • Soy milk (made from soybeans)
  • Soy yogurt
  • Silken tofu
  • Soy burgers/meat substitutes
  • Textured soy protein
  • Soy protein powder
  • Soy flour

Check out the Monash University FODMAP App for current data and serving sizes.

In summary, soy can be part of a low FODMAP diet and foods like edamame, tofu, and tempeh can add nutrients, variety, and flavor to any diet. If you haven’t yet, try my Colorful Asian Tofu Stirfry.

Want to learn more?

Read more Low FODMAP Tips

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