Tapioca Fiber or Soluble Corn Fiber: Which one is worse than sugar?
Most low carb and keto dieters know their way around a nutrition label and can spot suspicious ingredients in their sleep.
Yet, there are some ingredients on nutrition labels that appear fine at first glance– maybe they’re sourced from a familiar vegetable– but sound just a little off.
For us, one of these ingredients was tapioca fiber. We see it over and over again on low carb and keto-friendly product labels.
Fiber isn’t included in net carb counts, so on paper, tapioca fiber looks great. Still, with it being used in so many products, we wanted to dig deeper. We are glad we did.
In this article, we report on what we’ve discovered about tapioca fiber from available scientific research. We also provide evidence on whether or not tapioca fiber (and soluble corn fiber) are appropriate for diabetics, epileptics and those on a ketogenic diet. [Spoiler: One of them is not so good]
What is tapioca fiber?
So what exactly is tapioca fiber? It’s harder to explain than you would think.
For starters, tapioca fiber isn’t an ingredient that you can find at the grocery store (it’s not the same as the widely-available tapioca flour).
Search the internet for “tapioca fiber” and there’s no Wikipedia page. In fact, there aren’t many relevant results at all. Seriously, try it yourself.
Querying Alibaba for “tapioca fiber,” we started seeing random references to “IMO” sprinkled throughout the results. Interesting.
Does the term isomaltooligosaccharide ring a bell?
Quest Nutrition, makers of the popular protein bars, came under fire around 2013 for potentially misrepresenting IMO as dietary fiber on their bars’ nutrition labels.
Quest vehemently defended itself in a blog post. Yet, interestingly, just months later, they reformulated their recipe, removing IMO as an ingredient.
Why would a simple ingredient like dietary fiber be so important that people would seek litigation against Quest?
Dietary fiber has a host of healthful benefits, but for adherents of low carb and ketogenic diets, the most important aspect is whether or not fiber impacts blood sugar levels. That’s because a spike in blood glucose will result in an increase in insulin levels and insulin inhibits ketone production1.
To determine net effective carbs in the U.S., you normally take the total carbohydrate count and subtract out the amount of dietary fiber. This assumes that dietary fiber isn’t digested and doesn’t affect blood glucose.
But, if IMOs actually do affect blood glucose, then they shouldn’t be subtracted from the total amount of carbs. That means the net carb counts for products containing IMO are likely incorrect.
Does tapioca fiber = IMO?
That’s where it gets tricky. Tapioca fiber, as previously mentioned, is like a ghost on the internet. But, after some digging, we found a couple nutritional labels from well-known keto and paleo brands linking IMO and tapioca fiber.
Exhibit 1: Primal Kitchen
For our first example, let’s take a look at Primal Kitchen, a huge ($200 million) player in the Paleo foods market.
We’ll focus on the nutrition label for their Macadamia Sea Salt Grass-Fed Collagen Bars.
On Primal Kitchen’s website, the first ingredient listed for the Macadamia Sea Salt bar is isomaltooligosaccharides (from Tapioca). However, on Thrive Market, the first ingredient on the actual packaging is Prebiotic Tapioca Fiber.
That’s huge. Primal Kitchen considers prebiotic tapioca fiber the same as isomalto-oligosaccharides from tapioca.
Also note that Primal Kitchen lists 1g of fiber per bar, even though “tapioca fiber” is the main ingredient of the 49g bar. Read another way, Primal Kitchen does not consider prebiotic tapioca fiber as a dietary fiber!
Exhibit 2: Popular Low Carb Cookie Mix
Our second example comes from a popular low carb baking mix. On this ingredient list, you can clearly see that Soluble Tapioca Fiber is annotated with “IMO from non-GMO Tapioca starch.”
That’s as clear as it gets: IMO and Soluble Tapioca Fiber are linked on a single label.
Why should we place so much stock in what manufacturers are printing on their labels?
First, for Primal Kitchen, it simply behooves a brand of that size to closely monitor and comply with FDA labeling guidelines to avoid potential penalties. They have a lot to lose from mis-labeling.
Secondly, recall that tapioca fiber isn’t something that’s easy to find. If someone is buying tapioca fiber in bulk, it’s likely coming from China.
An example source is this large supplier from China, which can export 10,000 tons a month of “Organic Fiber Tapioca Syrup and powder.” However, the supplier lists their product under the known chemical registry number (CAS) for isomaltose, an IMO. Note, there is no CAS number for “tapioca fiber.”
Therefore, it’s very likely that food producers and manufacturers are purchasing what’s classified as IMO and consciously labeling it as tapioca fiber.
The Cost Factor
So, why are food manufacturers using tapioca fiber instead of soluble corn fiber? They could claim avoidance of GMO corn as a reason to use tapioca fiber. However it is very easy to find non-GMO soluble corn fiber (like the one we tested with).
Instead, cost may be a possible motivation behind utilizing tapioca fiber/IMO instead of soluble corn fiber. The soluble corn fiber we found was nearly double the cost per gram of popular IMO BioNeutra VitaFiber powder. In bulk quantities, that could potentially result in substantial cost savings.
The U.S. Food & Drug Administration (FDA) did not provide a definition of Dietary Fiber in food labeling guidelines until May 2016.
After releasing their initial definition of dietary fiber, the FDA called for manufacturers to submit scientific evidence via what’s known as a citizen petition. If manufacturers believed their “isolated” fiber should be included in the FDA’s list of dietary fibers, they needed to provide compelling scientific evidence to the FDA. Isomalto-oligosaccharide was indeed included in one of one of the petitions.
The FDA reviewed each petition and published a final guidance on dietary fiber in June 2018.
IMO did not make the cut in the FDA’s final guidelines on dietary fiber (June 2018).
Tapioca fiber (an alias for IMO) was also not on the list.
Between the food label clues and FDA review, the evidence points to IMO not being a true dietary fiber and tapioca fiber simply being a another name for IMO.
So, why should you care?
Tapioca fiber is worse than sugar
We’ve seen a lot of references to IMO floating around the internet that state the glycemic index of IMO is around 30. That’s not the GI of 0 that you’d expect from dietary fiber, but overall it’s not that bad. It’s about half the GI of table sugar, and on par with the GI of maltitol.
However, while looking through the literature, we noticed most studies focused primarily on IMO being a fiber and not on its glycemic impact.
Searching specifically for the effects of IMO on blood glucose, we found recent studies that compared IMO products from various producers and measured the effects of ingesting those IMOs on blood glucose levels2.
Across the board, even with the variances in producers and their methods of extraction, they found that IMOs generate an increase in blood glucose levels similar to glucose and dextrose.
Why is that important?
Glucose and dextrose both have a glycemic index of 100, which is higher than table sugar (65).
Not only do IMOs like tapioca fiber generate a glycemic response, they can generate a response that’s more substantial than the equivalent amount in sugar!
And take note: A GI around 100 is a huge difference from the GI values of around 30 that are floating around the internet.
What’s even more interesting is that these studies were not funded by competitors of IMOs looking to smear IMOs. In fact, we found that IMO producers generally funded the studies themselves.
IMOs are chained molecules of sugar that can vary in length, with longer lengths more difficult to break down 3.
One of the IMOs, isomaltose, is a disaccharide, meaning it has a length of only two glucose molecules held together by a bond. That bond can easily be broken down by enzymes in the body, releasing free glucose into the blood and spiking blood sugar levels.
The issue is that in most of the available commercial IMO products, isomaltose makes up nearly 60 percent of the supposed fiber content (think about the fiber content in protein bars). If you discount isomaltose as a fiber, most companies that advertise 90% pure IMOs actually have a product closer to only 30% actual fiber.
The same study also showed the molecular composition of IMO varies from brand to brand. There’s no strict definition from manufacturers regarding what constitutes an IMO. That means, a source of tapioca fiber could receive a Certificate of Analysis (COA) stating 90% fiber, even though the product only had 30%.
Why is there such a variance?
The starting ingredient for manufacturers is normally tapioca starch. However, companies develop what is called an enzyme cocktail, a proprietary set of food grade enzymes that are used to isolate the fiber from the starch. Simply put, manufacturers’ unique formulations will yield unique results. That makes it difficult for the consumer to know the exact purity of what they are ingesting!
What are some products I might know that use A LOT of tapioca fiber?
Tapioca fiber acts as a mild sweetener and thickener, which works great for products like chewy protein bars and baked goods, like cookies. Still, due to its versatile nature, it can sneak its way into many more categories of foods.
Let’s take a look at a real-world example from Smart Sweets, makers of the uber popular low sugar gummy snacks.
We chose Smart Sweets for our case study because tapioca fiber is the first item on the ingredients list of all their products. For their Fruit Gummy Bears, out of 50g in a serving, the label lists 28g of dietary fiber.
There’s some chicory root fiber as well, but because it’s listed after gelatin on the nutritional label we know that it’s equal to or less than 3g. That’s based on the fact that gelatin is a protein and there is only 3g of protein per bag.
In other words there is a lot of tapioca fiber per bag.
Considering the effect of tapioca fiber on blood glucose, you can treat those remaining 25g of fiber as 25 grams of sugar. Combined with the 3g of actual sugar, that means there are effectively 28g of sugar in a serving of Smart Sweets gummy bears.
Putting it to the test
With the above information fresh in our minds, we wanted to run a real-world test to confirm if this was all true (at least for us).
Again, with a whopping 28g of fiber listed per serving, most of which is tapioca fiber, Smart Sweets is perfect for our test.
Here’s what we tested:
- We fasted for 12 hours and then tested our blood glucose levels every 15 minutes after consuming a serving (50g) of Smart Sweets gummy bears.
- Since tapioca fiber is the main ingredient, we estimate that it accounts for 25g out of the 28g of fiber
- For comparison, in a separate test on another day, we consumed 28g of pure sugar dissolved in water. We also fasted for 12 hours and tested our blood glucose levels every 15 minutes during this test.
- Because the gummy bears contain 3g of actual sugar, we added that back into 25g to get 28g.
Here are our results:
As you can see in the graph, the measured blood glucose between the sugar water and Smart Sweets gummies was nearly identical. The data reflect significant increases in our blood glucose levels, basically doubling our starting values at peak.
Since Smart Sweets is comprised primarily of tapioca fiber, we attribute the glycemic response of the product to its tapioca fiber content.
Eating a serving of Smart Sweets gummy bears is essentially like taking a shot glass full of sugar.
And that’s not hyperbole– that’s essentially what our tests showed. Between those results and review of the scientific literature, the argument against tapioca fiber is compelling.
How can you avoid tapioca fiber and IMO?
The FDA’s final guidance on dietary fiber gives manufacturers up to January 1, 2020 to update their labels or reformulate their products.
Smaller manufacturers who sell under 10 million USD have an additional year to comply, until January 1, 2021. Yes, that’s around two and half years after the initial FDA guidance release.
That means that until the deadline is reached, companies may continue to label tapioca fiber as dietary fiber and still be in compliance. Until then, keep an eye out for large amounts of tapioca fiber and IMO on nutrition labels.
Are there any other names for tapioca fiber or IMOs on food labels?
Here are some ways we have seen tapioca fiber listed (watch out for these):
- Prebiotic Tapioca Fiber
- Soluble Tapioca Fiber
- Prebiotic Fiber from Tapioca Starch
- Prebiotic Soluble Fiber from Tapioca
- Non-GMO Tapioca Fiber
- Organic Tapioca Fiber
- Prebiotic Soluble Fiber from Cassava
The amount matters
To be fair, just because tapioca fiber shows up on a label, doesn’t necessarily mean it’s present in high quantities. If you see tapioca fiber or one of its alternate names on a label, look at the amount of fiber.
If the amount of fiber is relatively low and the tapioca fiber is farther down on the list of ingredients, the product as a whole may still fit into your low carb or keto diet. We simply treat the tapioca fiber as sugar and determine if we are comfortable with the amount (which sometimes we are!).
Example: A Keto Ice Cream
Check out this keto ice cream brand’s nutrition information.
Here, the there are only 2g of total dietary fiber per serving. Already, that shows the impact will be low. But also note that chicory root fiber is listed as an ingredient higher up on the list, meaning most of the fiber isn’t from tapioca fiber but rather from chicory root fiber. Even more, guar gum also contributes to the fiber content.
As you can see, there is approximately 1g of tapioca fiber per serving (if that). So in cases like this, we’d treat that 1g of tapioca fiber like sugar. This amount is reasonable considering even the most “keto” friendly foods (avocado, macadamia nuts) all contain some sugar.
So, now what? Are there FDA-approved dietary fibers out there?
The evidence is stacked against tapioca fiber. So what fibers are FDA approved?
Here’s a list of some common FDA-safe terms for dietary fiber that you may encounter. (Hint: Neither tapioca fiber nor IMO is on the list).
- Soluble corn fiber, resistant maltodextrin, resistant dextrin, resistant wheat dextrin, soluble wheat fiber, wheat dextrin
- Inulin, chicory root extract, chicory root, chicory root fiber, inulin from chicory, chicory vegetable fiber, fructooligosaccharide, oligofructose
- Psyllium husk, psyllium, psyllium seed husk, ispaghlua husk.
- Guar gum, locust bean gum, carob bean gum, carob seed gum
- Pectin, hydrolyzed pectin, fruit pectin, citrus pectin, modified pectin
- Cellulose, microcrystalline cellulose, cellulose gel, cellulose powder
- Barley beta fiber, barley betaglucan
- High-amylose maize starch, high-amylose corn starch
Note, it’s not by accident that IMO aliases sound eerily similar to these approved fibers. That’s exactly why ingredients like tapioca fiber fly under the radar.
Soluble Corn Fiber: Recognized by the FDA
We’ll use soluble corn fiber as an example since it’s the ingredient Quest Nutrition swapped out for IMO. Plus, many popular low carb and keto-friendly products currently on the market use soluble corn fiber.
You can read the FDA’s entire science review on soluble corn fiber, but suffice it to say, the empirical evidence points to soluble corn fiber acting like a real dietary fiber within the body.
Testing Soluble Corn Fiber
While Quest did their due diligence and included links to research in favor of soluble corn fiber, we still had to put it through the wringer, just as we did with tapioca fiber.
We determined that Quest protein bars contain around 15g of soluble corn fiber per serving. So, we dissolved 15g of soluble corn fiber in water, drank the mix and tested our blood levels.
Here’s what we found:
The results show a very minor increase in blood glucose, a far cry from what we saw with the tapioca fiber gummies. We used 84% pure corn fiber, so we anticipated a small effect on blood glucose levels.
Overall, the data on soluble corn fiber matches the expected results from the literature, FDA science review and ruling. Unlike tapioca fiber, soluble corn fiber acts like a fiber.
Source Still Matters
The fibers we’ve discussed are all isolated using various processing methods. As a result, the purity and fiber content can vary. Promitor, a soluble corn fiber brand, produces SCF products that contain either 70% and 85% fiber content.
Since products aren’t going to disclose the purity content of their SCF, we have to assume that products will be using the 70% fiber SCF. As a result, we will reduce the fiber count on the label by 30%. Basically, for every 10g of SCF on a label, treat it only at 7g of fiber.
That was a lot to digest, so here are some key points:
- IMO causes blood glucose levels to rise.
- The glycemic index of IMO is higher than that of sugar and is close to 100.
- Tapioca Fiber is another name for IMO on nutrition labels.
- The FDA has provided its final guidance for dietary fiber. IMO and tapioca fiber are not on the list of accepted dietary fibers.
- You may not see dietary fiber label changes in the U.S. until 2021.
- The amount of tapioca fiber is important in determining the level of diabetic or ketogenic friendliness of a product. You should be able to tolerate low levels of tapioca fiber on a low carb or ketogenic diet.
This was a tough article to research and write. In the past we had favorably reviewed (and eaten!) products with substantial amounts of tapioca fiber. In light of our findings, we have gone through and updated any affected reviews.
If anything, this is a reminder that testing your blood glucose levels is the only way to be certain if a specific food will affect your blood glucose levels. In fact, anyone can easily replicate our tests. So make sure to test for yourself!
While we found a lot of evidence against tapioca fiber, new research comes out all the time. Manufacturers always come out with new ingredients and methods. We can only base our decisions off of the products and research that are out there today.
In today’s world, it is unrealistic to completely avoid prepared snacks and foods. We rely on convenient food options to make it easier to maintain a long-term ketogenic lifestyle. It’s just important to be aware of how the ingredients affect your metabolism and make a decision accordingly.
The Kid Factor
We have found many No Sugar Added candies that contain high levels of tapioca fiber (50% or more). These products generally market to parents trying to limit their children’s sugar intake. Naturally, these products’ messages typically center around being anti-sugar. Yet, based on our findings, the metabolic effects of tapioca fiber are strikingly similar to sugar. Meanwhile, brands like Smart Sweets continue to campaign against sugar.
We hope to spread this information to keep people informed and push manufacturers to make changes. As Quest has shown us in the past, pressure and evidence can lead to positive changes.
Based on our research (and our personal test results), we will be avoiding products containing HIGH amounts of tapioca fiber.
Do you consume any products with tapioca fiber and/or IMOs? What has been your experience with these products? Please let us know in the comments.
If you know anyone who would find this information useful, please help spread the word!
You might also be interested in: How ketosis actually works and what no one tells you
- Mahendran Y, Vangipurapu J, Cederberg H, et al. Association of ketone body levels with hyperglycemia and type 2 diabetes in 9,398 Finnish men. Diabetes. 2013;62(10):3618-26.
- Gourineni, Vishnupriya et al. “Gastrointestinal Tolerance and Glycemic Response of Isomaltooligosaccharides in Healthy Adults” Nutrients vol. 10,3 301. 3 Mar. 2018, doi:10.3390/nu10030301
- A Survey of Commercially Available Isomaltooligosaccharide-Based Food Ingredients.Madsen LR 2nd, Stanley S, Swann P, Oswald JJ Food Sci. 2017 Feb; 82(2):401-408.
Sonja & Thanh: foodies at heart, globetrotters and avid discoverers of keto, low carb and organic products. Based out of Austin, Texas, we scour the world for food options that fit our healthy, active lifestyles.Learn more