Who doesn’t want to have their (keto) cake and eat it too? It’s safe to say that most people following the ketogenic diet have that one carb-heavy weakness that could easily knock them out of ketosis if they were to indulge. So what do you do? You find the keto equivalent of those sweet-tooth snacks.
It’s astonishing how many great-tasting keto cookies, cakes, and protein bars have hit the market over the last few years. It’s the best of both worlds: you get to enjoy that familiar guilty pleasure while keeping your body in a state of ketosis. The problem is that not all of those keto-friendly sweeteners are truly keto-friendly.
Soluble tapioca fiber has come under fire in 2019 as there is a lot of confusion over whether it is actually a low-carb ketogenic fiber or if it will spike blood glucose. Let’s discuss what true soluble tapioca fiber is, why its name has been tarnished, and what you should look for when buying a keto-friendly product.
What is Soluble Tapioca Fiber?
Soluble tapioca fiber is a ketogenic-friendly sweetener that is being used in many of your favorite products. It is made from non-GMO corn syrup that has been broken down through an enzymatic-based process, leaving you with a true keto-friendly fiber.
What is a True Keto Fiber?
This means that the fiber will not have an impact on your blood sugar, ensuring you’ll stay in ketosis. According to the new FDA announcement, “dietary fibers are defined as naturally occurring fibers that are intrinsic and intact in plants, or as isolated or synthetic fibers that have demonstrated a beneficial physiological effect.”
For example, when you eat a carbohydrate-heavy food such as rice or bread, glucose enters the bloodstream and your blood sugar rises. If you were following a ketogenic diet, upon eating the carbohydrate, your body would begin using the new source of glucose as fuel, knocking you out of ketosis.
However, if you were to eat a fibrous food such as broccoli or cauliflower, your blood sugar would not rise, and the body would continue running off ketones.
It goes without saying that for a product to be keto-friendly, it must be made with a true, legitimate fiber, one that doesn’t increase blood sugar levels. This is why soluble tapioca fiber has become so popular. It’s sweet, a natural binder, and keto-friendly. But as it turns out, some companies have been falsely using the name of this ingredient in order to push supposed keto-friendly products.
What’s the Issue with Soluble Tapioca Fiber?
Unfortunately, there are many brands that are claiming soluble tapioca fiber is in their keto products, but in reality, they are mislabeling the products. The most notorious example of the mislabeling of soluble tapioca fiber involves an additive called isomaltooligosaccharides.
What are Isomaltooligosaccharides (IMOs)?
Isomaltooligosaccharides, more commonly called IMOs, are a starch-sourced syrup that is high in maltose. Coming from sources such as corn or potatoes, IMOs are made up of short-chain carbohydrates, which gives them a distinct slightly sweet profile.
Since IMOs are a fiber that tastes sweet, they became incredibly popular for protein bars, supplement powders, and cooking ingredients, but there’s a catch: it’s not a true fiber.
Recent studies have found that IMOs directly impact your blood glucose (blood sugar levels). Researchers found that subjects’ glucose rapidly increased to 125 mg/dL after consuming IMOs. At the conclusion of the study, researchers deemed IMOs to have a glycemic index of 35. To put that into perspective, table sugar has a glycemic index of 65. 1
This means that eating a supposed keto-friendly product containing IMOs could knock you out of ketosis, ruin all your hard work, leave you frustrated, and make you wonder why you aren’t achieving your goals.
IMOs vs. Soluble Tapioca Fiber: Where’s the Confusion?
If IMOs are not a true fiber, how is it that they are getting mixed up with soluble tapioca fiber?
Both corn and tapioca are starch-starting sources to produce isomalto-oligosaccharides (IMOs) and soluble tapioca fiber. Despite having the same starting starch, IMOs and soluble tapioca fiber have completely different structures and physiological functions. This is why one is a true fiber and the other is not.
Since they share the same base, companies using IMOs take creative liberties to label their products under different names. As a binder for supplements, especially protein bars and powders, companies have labeled IMOs in various ways:
- Vegetable Fiber (Corn/Tapioca)
- Prebiotic Fiber (Corn/Tapioca)
- Soluble Corn Fiber
- Soluble Tapioca Fiber
Deeper Dive Comparison
Disclaimer: This next section is going to take a close look at IMOs vs. soluble tapioca fiber. Advanced terminology is used here, so if you want to skip that and learn more about how you can spot keto-friendly products in the store, jump to the next section: “What is Changing in 2020 (2021)?”
Why IMOs Are Not a True Fiber
IMOs are a glucose polysaccharide with polymer lengths of 2 to (n) (dp2 – dpn). The IMO gluco-polymer consists predominantly of alpha 1,4 and alpha 1,6 bonds which are partially digested but less fermentable than short chain polymers Inulin, FOS, XOS, & GOS.
Since IMOs do not resist digestion completely in the human small intestine, fewer polymers reach the colon for fermentation by gut microflora. IMOs are ~60% sweet as sucrose, which can be attributed to the polymer composition including di-saccharides (dp2) maltose and maltotriose. These compounds account for the sweet taste of IMO.
The characteristic bond type of IMOs allow for partial digestion in the small intestine and may also result in free glucose causing blood sugar spikes for certain individuals. The digestive resistant fraction of IMOs is also subject to debate and may be as low as 30% or less. AOAC testing methods do not capture IMO polymers as a fiber.
The Takeaway: The FDA does not recognize IMOs as a fiber and as of January 1, 2020, IMO polymer must be labeled as a caloric sugar with 4.0 calories per gram. More on this below.
Why Resistant Dextrin (RD) is a True Fiber
FiberSmart® is a resistant dextrin (RD), which is composed of digestive resistant glucose polymers of dp3 and higher with a verifiable enzyme resistant fraction of > 89% by FDA approved AOAC method. The polymer bonds of FiberSMART® resistant dextrin are composed of approximately 30% alpha 1,2 / alpha1,3 / and some beta linkages.
As such, RD/RMD is not completely digested and has a caloric value of ~ 1.4 – 2.0 kcal/g. During processing of FiberSMART®, the small polymers dp1 and dp2 are removed. FiberSmart® is neutral in flavor with a relative sweetness to sugar of ~ 20-30%.
As an RD, FiberSMART® exhibits the characteristics of fermentability, increased absorption of minerals, etc.
The Takeaway: The FDA recognizes RD/RMD as a functional soluble fiber, regardless of the starting starch source (corn, tapioca etc.).
What is Changing in 2020 (2021)?
Since the FDA does not recognize IMOs as a true fiber, as of January 1, 2020, large companies (>$10M in revenue per year) must label IMOs as a caloric sugar. Smaller companies (<$10M in revenue per year) have until January 1, 2021 to change their label for all products.
Supplement Nutrition Label: What to Look For
Supplement companies will begin changing their labels as soon as 2020, but in the meantime, take a moment to read the label of your favorite keto supplement. There are three ways to make sure your keto snack is going to help, not hurt your diet.
One way to ensure you are getting a legitimate keto product is to look for the Ketogenic-Certified logo on the packaging of your favorite products. These products have been tested for their metabolic response and pass the standards of the Ketogenic Certified program.
Some of the ketogenic-certified products that contain soluble tapioca fiber (resistant dextrin) are HEKA Bars and NUI cookies.
Alternative Names for Soluble Tapioca Fiber
Look for different names of true soluble tapioca fiber:
- Resistant Dextrin (RD)
- Tapioca Resistant Dextrin
Beyond Soluble Tapioca Fiber
Outside of soluble tapioca fiber, there are plenty of other keto-friendly sweeteners:
- Beta-glucan soluble fiber
- Psyllium husk
- Guar gum
- Locust bean gum
- Mixed plant cell wall fibers (a broad category that includes fibers like sugar cane fiber and apple fiber, among many others)
- Inulin and inulin-type fructans
- High amylose starch (resistant starch 2)
- Resistant maltodextrin/dextrin
- Cross linked phosphorylated RS4
Legitimate Soluble Tapioca Fiber: A Ketogenic-Certified Ingredient
The challenge is in today’s market as most companies will mix and match and improperly label products in order to avoid any backlash. Soluble tapioca fiber as referenced in relation to FiberSMART® or resistant dextrin is a true keto-friendly fiber that is an ideal additive for your favorite keto products.
- Lowery RP, Wilson JM, Barninger A, et al. The effects of soluble corn fibre and isomaltooligosacharides on blood glucose, insulin, digestion and fermentation in healthy young males and females. J. insul. resist. 2018;3(1), a32. https://doi.org/10.4102/jir.v3i1.32
David James Sautter is a fitness writer with over a decade of experience in the industry. After graduating with a Bachelor of Arts in English and Secondary Education, he earned certifications as a NASM-certified personal trainer, NASM-certified fitness nutrition specialist, and ACE-certified sports conditioning specialist. Merging his two passions, he has been the driving creative force behind articles, e-books, and training guides that cover a range of health and fitness topics with an emphasis on the ketogenic diet.