Oat Fiber vs Oat Flour: What’s the Difference? Are they Keto?

With so many types of oatmeals and oat products on the market today, it can become confusing which is which. In this post, we’ll cover the differences between oat fiber vs oat flour, the benefits of each, how you can substitute one for another in baking, and which one is suitable for a keto diet.

Let’s dive in!

Key Differences Between Oat Fiber vs Oat Flour

Oat flour is made from ground-up oats containing carbohydrates. Oat flour contains vitamins, minerals, protein, and fiber and is used as a gluten-free substitute in baking.

Oat fiber is an insoluble fiber made from grinding the oat hull. Oat fiber has no carbohydrates or fats and no real nutritional benefits. It is used in baking to help reduce carbs and add more fiber to a diet.

Oat Fiber

Oat fiber is considered an insoluble fiber as it is made from the ground outer shell or the hull of the oat grain. It is a manufactured byproduct resulting from separating the oat groats from the husk or inedible hull.

Oat fiber is pure insoluble fiber consisting of lignin, cellulose, and hemicellulose. Since it is insoluble fiber, your body cannot digest any nutrients from it, passing through the intestines undigested.

Oat fiber can be used in cooking and baking recipes. Some use it in baking as a way to add bulk to a recipe and up the fiber intake without adding caloric value.

The body can not process oat fiber into calories, which is why oat fiber has gained popularity with low-carb baking and low-carb diets such as the ketogenic diet. It can be used as a replacement or partial replacement for sugar or carbohydrates, so recipes still have fiber and some bulk, but without adding additional calories.

Oat fiber is naturally gluten-free. If you have gluten sensitivity, look for certified gluten-free products as regular oats have been known to get cross-contaminated with gluten products.

Health Benefits of Oat Fiber

While oat fiber does technically have has a few carbs, since oat fiber is insoluble fiber, the body cannot process it, causing it to pass through the digestive system seemingly intact. Therefore, it essentially has zero carbohydrates, fats, or protein and no real nutritional value.

The main advantage of oat fiber is that it is a rich source of insoluble fiber. Oat fiber can be a great option if you aren’t getting enough fiber in your diet. As an insoluble fiber, it can help people who face chronic constipation by helping the body to move toxins out of the body. Insoluble fibers can help reduce constipation while also helping you feel fuller for longer. It also may help reduce overall LDL cholesterol.

Oat Flour

Oat flour is a whole grain flour made from grinding oats (most commonly rolled oats) into a fine powder. Oat flour contains all the nutritional values found in the type of oats the flour is ground from.

Oat flour has become an increasingly popular gluten-free alternative to all-purpose flour.

Health Benefits of Oat Flour

Oats are traditionally rich in manganese, molybdenum, phosphorous, copper, biotin, vitamin B1, magnesium, chromium, and fiber. While also containing antioxidants, carbohydrates, and protein.

Oats are a heartier and more filling grain. They contain higher amounts of fat and protein than many other grains. All while being gluten-free! Studies have also shown that oats may help lower blood sugar levels as well as HDL levels.

How to Make Oat Flour

Making Oat Flour with Oats

If you don’t have oat flour or just find it more economical to make your own- the good news, it’s pretty quick and easy to make oat flour.

  • Add any type of oats to a good blender, food processor, or coffee grinder. Blend for just a minute or two until they are ground into a fine powder. Oats are soft, so they break down fairly quickly and easily.
  • 1 1/4 cups of oats will yield about one cup oat flour.
  • That’s it, really! You have oat flour!
  • If you choose to store them- choose a dry place away from moisture. An air-tight container or sealed bag will work best.

Is Oat Fiber or Oat Flour Keto?

Oats are filled with carbs and have little fiber, so they’re not considered a ketogenic food and are not suitable for a keto diet.

Oat fiber is keto as it is made up of pure insoluble dietary fiber, which leaves zero net carbs making oat fiber a keto-friendly ingredient.

Oat Fiber Substitutes

Oat Fiber can be used to replace volume lost when leaving sugar out of a recipe or using stevia instead of sugar.

Some have found that psyllium husk powder will work in recipes as a substitute for oat fiber. Psyllium husk powder is a form of fiber made from the husks of the Plantago ovata plant’s seeds.

While oat fiber can not be used as a 1:1 substitute for oat flour, you can do a partial substitution of 1/4 the total amount of oat flour which can help lower the overall carb count. For example, if a recipe calls for 1 cup of oat flour, you could use 1/4 cup of oat fiber and 3/4 cup of oat flour, which would help reduce the carbs and calories. This means you can substitute 1/4 cup oat fiber for oat flour out of every 1 cup of oat flour the recipe calls for.

Oat Flour Substittues

Regular flour, white flour, or all-purpose flour can be used to substitute for oat flour using an equal amount of oat flour by weight (not by volume).

Rice flour is a good substitute for oat flour that is gluten-free. You can use a 1:1 substitute ratio for oat flour to rice flour.

Another gluten-free option is using almond flour. Almond flour is similar in its baking qualities to oat flour in that it contains a lot of fiber and is not excessively absorbent. Almond flour is full of fiber and minerals and will add a mild nutty flavor.

What is Oat Bran?

Oat bran is different from both oat fiber and oat flour. Oat bran comes from the outermost part of the oat groat.

Oat bran is part of an oat grain. An oat grain is processed to remove the inedible exterior body of the grain (the oat fiber). This leaves behind the oat groat, and Oat bran comes from the outermost part of this oat groat kernel.

Oat bran is less processed than oatmeal and more nutritionally intact while containing more fiber, both soluble and insoluble, than oatmeal.

Due to their structure, many oat groats and oats (like steel-cut oats or rolled oats) may contain some oat bran. However, whole oat bran is also sold and is a great way to add soluble fiber to your diet.

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Author Biography

Karla Kueber is a Certified Evidence Based EFT Practioner and Health Coach, with a double Masters Degree in Education. She works with people to overcome emotional eating, curb cravings, and overcome resistance to eating new healthy foods. You can learn more about coaching with her here.