Oat Fiber vs Oat Bran

oat fiber vs bran imgOat fiber, bran, flour…what’s the difference? I get it. When I was a kid, you had two choices: instant or old fashioned oats. The world has changed. But it’s OK…they may have fancy names and look a little different, but these products are still healthy oats at heart. And they’ll open up whole new realms of possibilities in the kitchen (hello healthy oat berry breakfast cake!)

berry breakfast cake

See what I’m saying? WAY more appetizing than your standard bowl of oats if you ask me. It’s time to get friendly with the new types of oats! I’ll walk you through the most common types of oat products, and even the uncommon ones so you’ll know exactly what you want to buy and use in your own kitchen.

oat groat img

Can you believe that so many different products come from this one little grain? And it looks a little like a grain of wheat. But it’s not…that’s an oat groat, and the source of almost every product I’m highlighting today.

For most of us, oats can be a wonderfully healthy grain and a good source of natural slow burning carbs. Oats are often even well tolerated by those with gluten intolerance so long as the brand of oats you’re using are labeled gluten free. (Most brands of oats are processed in facilities that also process wheat so they are cross contaminated.) I would like to remind you quickly that food is never one size fits all. As with any food, it’s only healthy if your body processes it in a healthy way. So keep that in mind when trying oats as a part of your diet.

Oats for Cereal

Probably the most common oat product in your grocery store is old fashioned rolled oats. It’s a pantry staple here, and it consists of the whole grain that’s been steamed and rolled flat so that it cooks up quickly.

rolled oats img

Quick cooking oats (not pictured) are simply rolled oats that have been chopped up into finer pieces so that they’ll cook even faster. Quick cook oats include some oat flour to create that instant brothy texture to your bowl of oatmeal. Unfortunately, that can also jack up how quickly your body has access to the carbs. And spiking blood sugar is not so nice for the waistline. For this reason, quick cooking oats are not recommended to eat as a cereal for those wanting a slower burning grain on plans like Trim Healthy Mama. If you want to stick to a more low carb approach, you *can* use quick cooking oats to grind into flour. Using the flour in a solid baked good vs. a broth will bring down the glycemic index. See “how to make oat flour” below.

steel cut oats imgThe Irish cousin, steel cut oats are made from the whole oat kernel or groat that have been chopped into coarse pieces. This give a chewier bowl of oatmeal that has a bit more tooth to it, and it does take longer to cook. This is the type of oats that I prefer as cereal, and they stand up well to longer cooking for slow cooker recipes.

Oat Flour, Fiber & Bran

But what about the more unusual oat products like oat flour, fiber, and bran? Let’s take a closer look.

Why Oat Flour?

I first saw oats being used in a lower glycemic pancake recipe from the book Trim Healthy Mama. They were so good that I started to experiment on my own with oat flour in other recipes. I’ve found that it makes a nice, soft cakelike finished product. I love it in breakfast breads and muffins, like this banana cream cake, and berry breakfast cake.

oat flour imgI would not choose oat flour for recipes where you want a crunchy crust or the stretch and rise that you get with grains that contain gluten, but it’s a great fit for breads, cakes, cookies, and muffins.

How to make oat flour:

If you’ve got a blender and any type of oats in your pantry you’re in business. You’re seconds away from a batch of freshly ground oat flour.


  1. Measure out the amount of oats you’ll need into your blender.
  2. Blend until powdered
  3. Remeasure the flour amount needed for your recipe.
  4. You can use right away or store extras in the pantry or freezer for the next recipe.

Important note:   If you’re gluten free, be sure to use gluten free oats.

I usually have the old fashioned style oats on hand, but you can use ANY type of oat to create flour. You can even use the quick cook oats here with no problems. But WAIT! (I can hear my Trim Healthy Mama friends gasping)

“The Trim Healthy Mama book says not to use quick cooking oats, right?”

Yes it does. It says not to use them to make oatmeal. But if the final product will be baked into a solid, the glycemic index is manageable for oat flour. So you can use your leftover quick cooking oats to make oat flour!

What Is Oat Bran?

oat bran imgOat bran is made from the outmost bran or edible covering of the oat. The bran contains carbs in the form of both soluble and insoluble fiber, fat, and protein.  Nutrition wise, oat bran is higher in fibers than regular rolled oats, but still contains a similar nutrient profile. (True confessions: Y’all, the photo is actually wheat bran, but it looks very similar to oat bran. Sorry! My Trader Joes was out of oat bran!)

What is Oat Fiber?

Oat fiber is ONLY the insoluble fiber (lignin, cellulose and hemicellulose)- it’s made from grinding the non-digestible oat hull. This is the one product that’s *not* made from the humble groat you saw at the top of this page. It’s made from the hull or husk that the oat was harvested from.oat fiber imgNutrition wise, oat fiber is really more akin to sawdust than to oatmeal. It does contain some nutrients, but because it’s essentially non-digestible, it does not provide any nutrients or carbs for the body to burn. But that’s OK, because it’s not used for its nutritional properties.  It’s used in low carb baked goods as a flour sub either on its own or in a blend of other lower carb flours. It’s very affordable and very absorbent-oat fiber is capable of absorbing a lot of liquid in a recipe and can be used to add moisture to baked goods. Since oat fiber doesn’t break down in the digestive track it also helps to prevent constipation by bulking up the stool.

All in all, oat fiber is the odd cousin in the oat family, but it’s so affordable that it’s definitely worth trying out. You can find it here in the Trim Healthy Mama store (affiliate link).

Sheri Graham has perfected the art of baking with oat fiber. If you’re just getting started with this low carb flour, try her fun collection of single serving size Fuel Pull cakes made with oat fiber!


Doesn’t this look yummy!

Oat Fiber vs. Oat Bran

This was a common question when I used to admin on the THM Facebook groups. Oat bran is not a good sub for oat fiber if you’re needing to be carb conscious. The bran still contains lots of soluble (digestible) carbs, fats, and proteins, making it more akin to rolled oats in its nutrient profile. The texture of bran and fiber are drastically different as well.

What Should I Buy?

I usually just keep Old Fashioned rolled oats for baking and making flour, and Steel Cut oats on hand for cereal. Both rolled oats and steel cut oats are great healthy sources of natural carbs. I also keep a stash of very affordable oat fiber, and add it as an extender to some recipes to lower the carb count.Oat fiber is a great choice for very low carb baking, and for adding fiber to your diet.

If you’d like to know more about the nutrition comparisons between the different oat products, I’ve prepared a simple and lovely Oat Nutrition Report just for my subscribers! Pin, and then scroll down to download this sleek little Oat Nutrition Report that includes an exclusive new recipe!

To pin!

oat fiber bran pin

 Join my weekly e-newsletter and you’ll get access to this free report and more exclusive content just for my subscribing friends! ♥


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  1. amber g says

    Thank you! This is all very helpful :) You mentioned it being ok to ground the quick oats into flour and baking with them (for THM)… is it also ok to use the quick oats, without grinding them into flour, in other baked goods as well and be able to stick in an E setting? (example: baked oatmeal, etc). I’m wondering, because where we live, I can buy quick oats for about half the price of old fashioned rolled oats. Thank you!

  2. Allison Z says

    Ok. I went to order oat fiber from Amazon (i have a gift card) an. only saw “oat bran fiber”. I found your page explaining the difference but that totally confused me. The seller says it’s better than just oat fiber, but I’m not sure if it’ll work for what we’re using it for. Any ideas?

    • says

      It’s oat bran *with* fiber…great question. :) They say it’s “better” than oat fiber because it does have nutritive value to it. But it’s also carbier than oat fiber…so you really can’t use them interchangeably. Last I saw, my Amazon source was out of stock. I do have it listed on my THM Amazon store under flours.

    • says

      You can use it, but you’d consider it a carb source just like oats. :) Adding to to a yogurt parfait or to your oatmeal would be a great way to use it up!

  3. Donna says

    I’m a little scared to eat this oat fiber. Really sounds like a miracle because of no carbs, but useless nutritionally. I have hiatal hernia, aggravated guts, n am kind of afraid of the effect of the oat fiber in my gut n tummy. Don’t like how it absorbs so swiftly. Guess that’s good in a way, but that could be bad n really cause trouble if a person isn’t paying attention. Any helpful thoughts?

    • says

      Donna, if you have a fussy tummy that doesn’t handle fiber well, then it may not be a good fit for you. It’s not a miracle, it’s just pure fiber (carbs = to the fiber content, and none of it is digestible)

      You may be able to try it in a small quantity in a recipe (maybe try a teaspoon in a Muffin in a Mug recipe?) to decide if it’s something you want to use. But if other forms of fiber irritates your tummy, then you may just want to skip it. I’m a *big* proponent of listening to your unique body and tailoring foods that best suite you. :)

      P.S. It doesn’t absorb through the intestinal walls…it can absorb water well, but it’s not broken down and digested in your body. It’s 100% fiber, which *can* be a healthy fit for some, and not for others.

  4. says

    I’m wondering if you can answer a question since you seem to have a lot of information on oats! We live in Australia where oats are not recommended as part of a gluten free diet for celiacs. So, I am just wondering about purchasing gluten-free oat fiber from the US. My question is, do you know if the oat fiber contains the avenin protein or not? I guess it could be contaminated with it, but just wondering if it was actually part of the husk that is processed to make the fiber. I don’t seem to be able to find anything on the net about it.

    Thank you

    • says

      Avenin is the primary protein found in oats, and according to animal feed sites, the hulls are “low in protein”, so my assumption would be that yes- they do contain avenin in small amounts. It may be helpful to search “oat hull composition”- there seems to be a fair amount of info and research on it in relation to animal feed. :)

  5. Sarah Turner says

    Hi! I’m wondering if it would negatively affect the texture of my dishes if I sub the oat fiber for oat flour in my own DIY baking blend?

    • says

      Hi Sarah,
      Oat fiber *does* have a very different texture than oat flour. I find oat flour to be softer. Maybe scale back to a single serving of mix and see what you think?

    • Tiffany says

      Sarah, I was just wondering if you ever tried subbing Oat Flour in your recipe. I was wondering the same thing. :)

    • says

      psyllium is a completely different plant than oats. (plantago family…same as this herb.) However, many people will sub one for another. But I find the psyllium husk to be more mushy and textural than the oat fiber in baked goods. The psyllium fibers are larger, and they bulk with water.

    • says

      You can use oat flour as an E ingredient. Oat fiber is a FP ingredient. So if the recipe is an S recipe, using significant amounts of oat flour would push you into crossover territory.

  6. LindaB says

    Hi…I found this article by googling Oat Bran and THM. Thank you for all your information!

    My question is : Can I continue to make and eat this “pancake” and be on the THM plan successfully?
    2 tbsp oat bran
    2 tbsp fat-free Greek yogurt
    1 egg white

    I have been eating thiis for years with a few pieces of turkey bacon.
    Would it work?

    • says

      If I calculated correctly, one T. of oat bran has about 3 net carbs. So the pancake should be on plan depending on your yogurt. Careful with the fat content of the bacon though…whether turkey or regular bacon, it’s a fatty meat, so that needs to be figured in toward your meal type. :)

  7. Ann says

    I just baked the THM Lemon Curd Cake, I haven’t eaten it baked, but the batter was not very pleasing; I used a mixer to mix it and not a food processor as recommended in the recipe. It barely rose. Would a good processor have produced a better product?


    • says

      I haven’t tried that particular recipe, but I don’t use a food processor to mix batters. I can’t imagine that it would have made that much of a difference?

  8. Angie says

    So if you are ‘allergic’ to oats, would the oat fiber in the THM baking blend be reactionary to you? It seems like it would, but I really like the baking blend & like using it!

  9. Christine says

    So can you use Oat flour instead of the THM baking blend. We can’t have the almond flour in the baking blend because of an allergy and so I am wondering about an alternative. I can’t find oat fiber anywhere in the stores else I would make the baking blend myself and leave out the almond flour. Would oat flour be the right substitute for that.

    • says

      Hi Christine! Oat flour is one that I particularly enjoy, as it has such a soft, muffin like texture when it bakes. It IS on plan, but it’s also definitely in E territory, since it’s a whole grain. Oat fiber on the other hand is FP, which is why it’s the backbone of the baking mix. It has very little fuel in it at all, and provides a nice base to mix with other low carb flours. I’d recommend buying a bag and trying it, and maybe reserving your homemade mix for just S or FP treats, and use the oat flour (which is cheaper and easy to make from regular oatmeal) for E treats. :)

      I use oat flour here and here!

  10. Ella says

    I was wondering what the difference was between oat bran and oat fiber. Thank you for a wonderful explanation! I do appreciate it.

  11. Patrice says

    I just started to use oat fiber. Can it or any of the other low carb flours be consumed without being cooked or baked? Like adding it, protein powder, and almond flour to almond butter and chocolate chip to make a quick no bake treat.


    • says

      Sure…oat fiber doesn’t have to be baked or cooked. In fact, I don’t know of any low carb flour that needs to be baked before consuming. Usually, it’s other ingredients in a recipe (like eggs) where baking before eating is recommended.


  1. […] No es lo mismo harina de avena, que fibra de avena (oat fiber) ni salvado de avena (oat bran). El salvado y la fibra se usa en muy pequeños porcentajes en los panes/galletas, la harina si se puede sustituir en mayor cantidad. La harina tiene carbohidratos, la fibra es 100% fibra insloluble util para la digestión, el salvado tiene pocos cantidades de carbohidratos y su contenido mayor es de fibra soluble (la que ayuda a bajar el colesterol y el azùcar en sangre). En este link pueden ver las fotos: http://gwens-nest.com/oat-fiber-vs-oat-bran/ […]

  2. […]   Gwen over at Gwens-nest is a true THM icon and hers was the first THM friendly blog I ever visited.  She is just the person to help us understand the difference between these two commonly confused ingredients!  I will admit that I mixed these two up for a couple of weeks when trying to make FP recipes.  If you don’t quite have the grip you’d like to have on  this subject here’s your opportunity to change all that… Gwens-nest on oat products: Oat Fiber vs. Oat Flour […]