Why Does Tofu Cause Gas? (+ What Can You Do About It)


Just about all beans cause gas to some degree, mainly because they contain significant amounts of oligosaccharides.

Since tofu is made from soybeans, it’s not surprising that tofu often causes gas for people who eat large amounts of it.

I’m going to explain why tofu causes gas and bloating in the simplest terms possible, and go over a few possible solutions.

Why Do Beans Cause Gas? (Including Soybeans)

The vast majority of gas comes from carbohydrates, not fat or protein (although protein with sulfur can affect the smell).

While some carbohydrates are easy to digest (e.g. glucose), others are not – fiber and FODMAPs.

Fiber and FODMAPs don’t break down much (or at all) in the stomach or small intestine, so they get fermented in the large intestine, which produces gas as a byproduct. If this gas builds up rapidly, it causes bloating until it is released (mainly through flatulence).

We won’t go into detail on all that, but in the context of soybeans, you’ll need to know that the “O” in FODMAPs stands for oligosaccharides, which are known to cause stomach problems even in relatively small amounts.

A Note on Silken vs Firm Tofu and Gas

block of tofu

Firm tofu has lower FODMAP content, which is due to how silken and firm tofu are made (source).

The pressing process that removes moisture from firm tofu also removes certain FODMAPs that dissolve in the water.

For people sensitive to FODMAPs, firm tofu is a better choice than silken tofu.

Fiber in Tofu

Let’s take a quick look at the macronutrient profile of tofu.

The data below is for 100 grams of firm tofu. Note that a block of firm tofu is usually about 300-400 grams total.

Energy (kcal) 144
Protein (g) 17.3
Total Lipid (g) 8.72
Carbohydrate (g) 2.78
Fiber (g) 2.3

Tofu is very low in carbohydrates, but almost all of that is in fact fiber.

Still, there’s not a ton of fiber in tofu. Even if you eat a full block, that’s about 10 grams of fiber. This is a significant amount of tofu, but a single serving of certain vegetables can get you that amount.

In other words, the raw fiber content of tofu might contribute a bit to gas, but shouldn’t cause huge issues.

FODMAPs in Tofu

The more common reason that beans and bean-products typically cause gas is because of the oligosaccharides in them.

Specifically, the oligosaccharides raffinose and stachyose.

It’s hard to find data on this, especially for tofu, but I was able to find oligosaccharide data for soybeans (source):

oligosaccharides in soybeans

Obviously we’ll look at “soaked” and cooked” data, since tofu is already cooked when you buy it. I’ve reproduced that data below:

  Soybeans (100 g)
Sucrose 1.71 g
Raffinose 0.23 g
Stachyose 0.11 g

Sucrose can cause some stomach trouble in large amounts, but the bigger concerns here are the raffinose and stachyose, even though they’re present in smaller amounts.

Still, soybeans (and logically tofu) have lower amounts of FODMAPs compared to most other beans (see data on chickpeas and gas here).

How Can You Reduce Gas From Tofu?

Unless someone has a soy intolerance, we’ve seen that tofu can cause some gas, but it shouldn’t be a ridiculous amount.

Still, if tofu or other bean-products give you excessive gas and bloating, there are a few things you can do.

First, you can buy sprouted tofu. While not every grocery store carries it, I assure you it does exist. Sprouting (i.e. fermentation) is one of the most effective ways to reduce oligosaccharide content in beans (source).

In addition, you can take a bean enzyme product like Beano alongside your tofu. These products contain the enzymes needed to digest oligosaccharides before they reach the large intestine.

FAQs About Tofu and Gas

Do beans other than soybeans cause people less gas?

Yes, certain beans other than soybeans may cause less gas for some people. While individual reactions can vary, beans such as lentils, mung beans, and adzuki beans are generally considered to be easier on the digestive system and may cause less gas compared to some other varieties like kidney beans or black beans.

What’s a good serving size of tofu to avoid excessive gas?

A typical serving size of tofu is around 3 to 4 ounces (85 to 113 grams). It’s advisable to start with a smaller serving size and gradually increase it, allowing your digestive system to adjust. Additionally, choosing firmer tofu types and pressing them before cooking can help reduce water content, potentially minimizing digestive discomfort.

Which foods are good to combine with tofu to reduce bloating?

To reduce bloating when consuming tofu, you can pair it with foods that are easy to digest and less likely to cause gastrointestinal discomfort. Here are some suggestions:

  1. Cooked Vegetables: Steam or lightly cook vegetables like carrots, zucchini, bell peppers, or spinach. These are generally easier to digest than raw vegetables.
  2. Grains: Pairing tofu with well-cooked grains like quinoa, rice, or couscous can provide a balanced and easily digestible meal.
  3. Fermented Foods: Adding fermented foods like kimchi or sauerkraut can aid digestion by promoting a healthy gut microbiome.
  4. Ginger: Incorporating ginger into your tofu dishes can have anti-inflammatory properties and may help with digestion.
  5. Herbs and Spices: Use herbs like cilantro, parsley, or mint, and spices such as cumin or coriander, which can add flavor without causing digestive issues.
  6. Healthy Fats: Include small amounts of healthy fats like avocado or olive oil, as they can contribute to a satisfying meal without being heavy on the digestive system.
  7. Lemon or Lime: Squeezing some lemon or lime over your tofu can not only enhance the flavor but may also aid digestion.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. I've spent over 6 years as a freelance nutrition writer and researcher. During this time, I've tested over 50 vegan protein powders, and over 100 other types of vegan supplements.

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