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What Is IMO? The Truth Behind “Healthy” Protein Bars

what is imo

what is imo

High-fructose corn syrup, artificial colors like red #3, and artificial sweeteners like aspartame… There's a whole laundry list of ingredients that most health-conscious consumers know to avoid. But there's one that often flies under the radar, and it could be lurking in your so-called healthy protein bar: IMOs.

What Is Isomalto-oligosaccharide (IMO)?

IMO is a high-maltose syrup made up of a mixture of short-chain carbohydrates. It is found naturally in some whole foods, but can also be manufactured to be added to packaged products. In recent years, IMO has become the holy grail ingredient for creating healthy processed foods like protein bars. It’s often marketed as a sweet-tasting, zero-calorie prebiotic fiber that has essentially zero effect on blood sugar.

Sound too good to be true? Let’s find out…

Why Is IMO Used in Packaged Food?

To say the average American has a sweet tooth would be an understatement. But it’s not our fault: Humans have evolved to seek out sweet, sugary, calorically-dense foods as a quick source of energy. Sugar was rare in ancient times, usually only found in seasonal foods like ripe fruits and honey. However, in today’s modern processed-food-laden world, sugar-sweetened foods and beverages are literally available on every street corner. Hello, obesity and metabolic disease.

The amount of sugar in most processed food is no surprise to anyone though, right? Luckily, consumers are becoming more well-informed and reading labels, looking for “healthy” options to snack on that are low in added sugar.

Protein bar manufacturers picked up on this need and started creating low-carb, high-protein energy bars. The hidden sweetening agent? You guessed it: IMO.

There are two main reasons why IMO was a seemingly genius addition to protein bars:

  1. It has a sweet taste, but contains fewer calories per gram than natural sugar.
  2. It’s believed to be a source of prebiotic fiber that doesn’t add to the overall net carbohydrate value of a food, making it marketable as “low-carb.”

A solution to the problem of producing a bar that's portable, high in fiber and natural energy – and doesn't taste like sawdust – had seemingly been found.

And as health-conscious consumers, we gobbled these babies up. Finally, a “healthy” bar with a low level of net carbs, relatively low calories, and high amounts of fiber and protein.

However, a deeper dive into the research shows that IMOs might not live up to their sterling reputation as a calorie-free, guilt-free source of dietary fiber.

The Problems with IMO

Most IMO Sources are Not “Natural”

There is no debating that IMO occurs naturally in some foods. However, it is not economically feasible to extract IMO from whole foods on a large scale, so most commercially-available IMO syrups are manufactured from starch using an enzymatic process. Because of their lower price points, these industrial, starch-based IMO sources are what you will find in the vast majority of the “healthy, low-carb” bars on the market.

Wait… Did we just use “starch” and “low-carb” in the same sentence? Something fishy here…

Industrial IMO Can Spike Blood Sugar

A 2017 study in the Journal of Insulin Resistance aimed to investigate the impact of IMO consumption on blood glucose, insulin and breath hydrogen responses in healthy men and women. The results of the study showed that IMO consumption led to a rise of nearly 50 mg/dL in blood glucose, with a five-fold rise in insulin at 30 minutes.

But that’s not all. Another 2017 study by the Journal of Food Science on IMO clearly stated:

“Analysis of the results with respect to digestibility suggests that the potential glycemic impact of the ingredients and products containing “industrial” IMO may be inconsistent with the product labeling and/or certificates of analysis with respect to overall fiber content, prebiotic fiber content, and glycemic response and are thus inappropriate for diabetic patients and those on low-carbohydrate (for example, ketogenic) diets.”

In other words, IMO does not function purely as prebiotic fiber and has been shown to significantly spike blood glucose in some individuals!

IMO Is Not Zero Calorie

IMO syrup contains about 2.7 to 3.3 calories per gram, and most protein bar manufacturers are using up to 15 grams in one serving to bump up the dietary fiber content. We don’t claim to be math wizards, but we’re pretty sure 15 times ~3 does not equal zero.

IMO Can Cause Digestive Distress

Oligosaccharides like IMO are large molecules that are not fully broken down in the digestive process. This is because the human body doesn’t actually produce the enzyme needed to digest them (alpha-galactosidase), so they can cause digestive distress in many people.

This is especially true for individuals with small intestinal bacterial overgrowth (SIBO) as the undigested oligosaccharide molecules can cause excess fermentation by bacteria residing in the small intestine, resulting in excessive amounts of gas and bloating. This is also why a low FODMAP diet is often recommended to those with SIBO; FODMAP stands for “fermentable oligo-, di-, mono-saccharides and polyols”. You can thank us during your next Trivia Night.

In other words, if your favorite protein or energy bar is giving you gas, you might want to investigate the label for IMOs (more on that below).

The Difference Between IMO and Inulin

Inulin is another common sweetener or additive in low-carb, low-sugar bars, and how it differs from IMO is a common question.

Inulin, while also an oligosaccharide, is not the same thing as IMO. However, it does have many of the same properties – and downsides – as IMO. There is some evidence that inulin may not have as deleterious of a blood sugar effect, but because of its ability to also cause severe digestive distress in some individuals, it is definitely not an ideal additive to a “healthy” energy bar.

How to Spot Fraudulent Fiber on a Label

IMO and inulin are sometimes tricky to spot. Here are some terms to look out for when trying to find inulin or IMO on a food label:

  • Fiber (IMO)
  • IMO Fiber (Powder or Syrup)
  • Isomalto-Oligosaccharides
  • Prebiotic Fiber
  • VitaFiber
  • Inulin
  • Chicory root


Here’s a recap: IMO, while marketed as a healthy low-carb, zero-calorie, high-fiber sweetener, is not all its cracked up to be. In reality, it’s often from unnatural sources, causes blood sugar spikes, gas, and bloating, and is definitely not zero-calorie.

Whether you're an athlete seeking a clean energy bar to fuel a race, an outdoor enthusiast wanting a healthy protein bar, or a parent looking for a wholesome snack for your kids, you're better off steering clear of bars containing IMO. Instead, opt for products that are made only with whole-food sources and ingredients you’d recognize in nature.

And when you have bars like the Kion Bar that are sweetened with nutrient-dense, organic honey and contain natural sources of fiber like almonds, chia seeds, and cocoa nibs, who needs IMO anyway?

32 thoughts on “What Is IMO? The Truth Behind “Healthy” Protein Bars

  1. An example of this is Smart Sweets. They taste amazing because it is full of liiiiieeeeesssss. It spikes the blood sugar so much. Only those who test their blood knows the truth that not all fiber is created equal.

  2. There must be a postgraduate program for ‘fuzzy’ labeling. Especially when it comes to ‘health foods’ and ‘all natural.’ My doctor told me to take a fiber in a pill. I read the label. It said that the pills were manufactured from “food grade fiber”. I took that to mean highly processed sawdust. Maybe from bamboo? I decided to try raw oatmeal Ninja’ed with milk and yogurt. Works for me.

    1. Chicory root is not inherently unhealthy. However, inulin is commonly derived from chicory, so manufacturers use the term “chicory root” or “chicory fiber” to mask the presence of the inulin in their products. That’s why it behooves you to look out for it as an ingredient.

      1. FYI, IMO is not made from chicory root. Chicory root is used to make inulin and thus IMO and inulin are not the same thing.

        I suggest you do better research.

  3. I just had a drink powder called super cacoa and maca breakfastBowl and I mixed it with mostly water and milk. I then after a little while got this weird feeling in my mouth almost numb. then I read the back and found it had a thing called IMO. I cannot handle fake sweetener it leaves a shocking taste in my mouth. It has to be honey or sugar or nothing. I got a bit of a fright it felt like I was felt as if I was going to have a reaction to it. wont be having that again.

    1. That numb feeling is 100% not IMO, IMO does not cause that. What other ingredients are listed on there, more than likely you are describing a sugar alcohol of some sort. I am in the food ingredients industry, and have tasted all these ingredients raw.

    1. Inulin is another name for IMO, so the concerns related to IMO would also be relevant for inulin

      Amendment: While inulin and IMO are both oligosaccharides, they are not exactly the same… However, they do share many of the same downsides/concerns, and we do not see either as an ideal inclusion to a clean energy bar.

      1. Team Kion, did you read Ben’s article? You are contradicting his writing. His article specifically says Inulin is NOT the same thing as IMO! The article also states that Inulin doesn’t raise blood sugar the way IMO does but it may cause digestive distress in some individuals, which is why I’m assuming he doesn’t recommend it. So the accurate response to the question, based on Ben’s article, is that while Inulin appears to be better than IMO, it’s still not considered a good source of fiber for protein bars.

        We get enough inaccurate nutritional information passed along from other news sources, don’t be one of them to misquote and muddy the waters. I follow Ben’s articles and listen to his podcasts because he delivers clear and accurate information, so please continue that trend on the Kion website.
        We’ll see if this comment is posted or taken down.

        1. Apologies, the above response was indeed too broad… More appropriately, inulin and IMOs are both oligosaccharides, but inulin is not exactly the same as IMO. There is some evidence that suggests that inulin does not appear to have the same deleterious effects on blood glucose as IMO. However, it does have many of the same downsides as IMOs and can be especially troublesome to digest for many. This is why we do not see it as an ideal inclusion for a clean energy bar. Thank you for keeping us accountable <3

  4. I am 68 yr old diabetic who weighs 168 and have been working out hard with weights and eating over 4000 calories. My insulin is low and I haven’t been able to gain.body fat is under 6 %.would like to gain 5 pounds and get glucose level down which is running high despite metformin.Ideas diet is clean

    1. Get an extensive full panel of bloodwork done, including mineral and micro nutrients, vitamin d, etc, to see if any of your levels are off. Most people are deficient in zinc and magnesium, but you won’t know what you are deficient in till you get bloodwork done. You want Red Blood cell tests for zinc and mag. Stan Efferding has a link and some youtube videos on this topic. If any of your levels are off, it make adding mass very difficult. Poor gut flora, low stomach acid, can negatively impact absorption. It’s a journey, good luck.

    2. IMHO -Get out of diabetes, dude. If your diet was clean you wouldn’t have diabetes. In this day and age almost anyone can ditch it. Get on keto diet. Chk out books by docs telling you how to get out of diabetes (Shallenberger & many others).
      Also, work out smart, not hard. Read “Body by Science”; it’s the bible of working out smart. HIIT beats regular exercise by miles. Lastly, cold thermogenesis can really help with diabetes. Good luck, dude. Hope you shake the D and gain some muscle.

  5. I just purchased some protein powder (Organika’s Vege-Pro) that lists “organic inulin powder” as an ingredient. Is this still just IMO/inulin or something as bad?

    1. Hi Marc, Basically, not all sources of prebiotic fiber created equal, and IMO is the one to look out for. If you check your blood glucose after you eat any bar with inulin and you don’t have a really high glycemic response, you should be fine.

    1. Hi Alicia, we’re not familiar with that product. Basically, not all sources of prebiotic fiber are created equal, and IMO is the one to look out for.

  6. One of my energy bar lists as an ingredient “Isomalto-oligosaccharide (prebiotic fiber from cassava root)” and the other lists “soluble corn fiber (prebiotic fiber)”. Are either of these ingredients the IMO the article is talking about?

  7. I’m always completely baffled why someone would even want to buy a commercial energy bar. A pocket full of almonds and dates, job done. If you need a bit of a boost from either carbs or fat, even better, get yourself into metabolic flexibility!

  8. What about taking psyllium husk and ground flax for fiber supplementation, do you have any experience raising of insulin levels with those ?

    1. Hi Jeff, this is a great question for the Kion Community. We will keep it in mind for a future article as well. Stay tuned!

      1. I’ve been curious about this as well – insulin response, does it take you out of a fasted state (I believe so?), etc.

        I find psyllium beneficial for a number of reasons, but if it’s going to negate the benefits of fasting, I’d like to know that beforehand so I can make an informed decision. Thanks!

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