Does Oatmeal Cause Gas and Bloating?


In general, oatmeal doesn’t cause excessive gas for most people.

However, there are a decent number of people who swear that oatmeal makes them bloated and more flatulent.

I’ll break down the simple reasons why oatmeal causes gas for some and not others in this short post.

How Would Oats Cause Gas and Bloating?

Gas is made as a result of bacterial fermentation in the gut.

It turns out that the vast majority of gas comes from carbohydrates that are hard to digest. They don’t break down in the stomach or small intestine, and are later fermented in the colon.

While there are a few different types of carbohydrates that can lead to this, the one you’re probably most familiar with is fiber.

Let’s take a quick look at the nutritional profile of oats (100 grams of raw oats):

Energy (kcal) 379
Protein (g) 13.2
Total Lipid (g) 6.52
Carbohydrate (g) 67.7
Fiber (g) 10.1
Sugars (g) 1

For reference, one cup of dry oats is about 80 grams (so about 8 grams of fiber).

The high carbohydrate content of oats can lead to excess gas. They are mostly starches, which digest fairly easily, but not as easily as simple sugar. Not all of them will always be fully broken down before the large intestine, especially if you don’t chew thoroughly.

How Too Much Fiber Can Lead to Gas

The main reason that oatmeal sometimes causes gas is its high fiber content.

In addition, most fiber in oats is soluble fiber.

Soluble fiber dissolves in water and forms a gel-like mixture that moves slowly through your intestines compared to insoluble fiber. This means that soluble fiber has more time to ferment.

And since soluble fiber bulks up, it typically encourages bowel movements. However, too much soluble fiber can lead to feeling “backed up”, and lead to bloating if it traps in gas.


Oatmeal is relatively high in soluble fiber, which is the main reason that it can cause gas, especially in people who aren’t used to eating much fiber.

Which Oatmeal Toppings Cause Gas?

One other thing to consider is that oatmeal is rarely eaten plain, and certain toppings might also cause gas (or at least contribute to it).

This can be the case whether you’re buying pre-made oatmeal, or adding toppings yourself.

Without going into excessive detail, the following common toppings can lead to an increase in gas (or worsening of smell):

Can You Reduce the Gas That Oatmeal Causes

If you’re having gas problems from eating oatmeal, there isn’t a ton you can do, but there are a few things.

First, the amount of gas from a meal is almost always proportional to the amount eaten, so just eating smaller portions of oatmeal may be a solution for some people.

In addition, chewing more thoroughly can help ensure that the starches in oatmeal are digested before passing through the small intestine.

Next, pay attention to the other ingredients in your oatmeal. You can test different combinations to see if certain ingredients lead to more gas for you than others.

Finally, if you’re not used to eating much soluble fiber, start with small servings and work your way up over time so your body can get used to it.

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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