The Truth About IMOs (and what they are)

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 (Isomalto-oligosaccharide)


What the heck is Isomalto-oligosaccharide (IMO)?

IMO is a high-maltose syrup made up of a mixture of short-chain carbohydrates. Yes, it’s found naturally in some whole foods, but most packaged goods add manufactured IMOs to their products (because it doesn’t occur in them naturally). In recent years, IMO has become the key ingredient for creating “healthy” low carb, low sugar, and high fiber foods like protein bars, pastas, ice creams, and even so-called “healthy” drinks. It’s often marketed as a sweet-tasting, zero-calorie prebiotic fiber that is supposed to have zero effect on blood sugar.

Too good to be true?


Why Is IMO Used in Packaged Food?

Thankfully, consumers are becoming more well-informed and reading labels, looking for “healthy” options to snack on that are low in added sugar, and protein bar manufacturers as well as other health food companies know this and want to meet their customers’ desires. So they picked up the need to start creating low calorie, low sugar, low carb, high fiber snacks using IMOs.

Why is IMO the common choice to add to protein bars and snacks?

It has a sweet taste, but contains fewer calories per gram than natural sugar.
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” and “high fiber”

This seems to be the solution to creating a healthy item that’s portable, high in fiber and still considered “natural.”

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…..And though I CAN speak from experience back in my 2014 days, my personal experience can only speak for myself….so let me show you other proof!


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. Because of their lower price points, these industrial, starch-based IMO sources are what you will find in the majority of the “healthy, low-carb” snacks on the market.

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. This 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 Can Cause Digestive Distress

Oligosaccharides 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.

In other words, if your favorite protein or energy bar is giving you gas, you might want to investigate the label for IMOs!

Is Inulin and IMO the same thing?

You may recognize “inulin” in your protein bar or drinks, as this is another common sweetener or additive in low-carb, low-sugar snacks, but how does it differ from IMO?

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 many individuals, it is definitely not an ideal additive to a “healthy” food item.

Read more about Inulin HERE in another blog post.



How to Spot Fake Fiber on a Label

IMO and inulin are sometimes tricky to spot and can also be disguised under other names. Here are some terms to look out for when trying to find inulin or IMO on a food label:

Fiber (note, this is fiber not naturally already in an item. So basically if they say “added fiber” it’s most likely IMO)

  • Isomalto-Oligosaccharides
  • Prebiotic Fiber
  • VitaFiber
  • Inulin / artichoke inulin / agave inulin
  • Chicory root / chicory root fiber
  • Corn fiber
  • “blank” fiber

Just to clarify on the last bullet point above, if fiber is being added to somthing (even if it’s natural, ex: “cassava root fiber” “artichoke fiber” etc.) that’s not naturally in the product (ex: soda naturally has no fiber, so if “cassava root fiber” added to soda even though the fiber is natural, having extracted fiber from a natural source and putting it into somthing else is now, NOT NATURAL.) Companies are trying to add “prebiotics” “fiber” and all other forms of IMOs to foods that naturally do not have them. This is an issue! If you want to add prebiotic fiber to your diet, eat those foods in their natural forms to get them! I cannot stress enough that removing somthing natural and putting it into somthing else isn’t as “simple” as it reads…..there’s are many steps and a long proccess it goes through via extraction, formulation, and processing in a plant using chemicals to achieve extraction. In the end, it’s not natural anymore!


Dietary fiber (DF) products are often obtained from plant sources using chemical processes. The main purpose of the extraction, purification and isolation of DFs by chemical methods is to obtain the best possible yield of DF compounds generating food ingredients with the best functionality and health benefits. Functional properties of interest include those related to gelling capacity, oil and water holding capacity, and swelling capacity, while physiological benefits relate to the production of short chain fatty acids during the microbiota fermentation of DFs, and the ones related to the presence of phenolic compounds in DFs. An understanding of chemical extraction requires knowing the DF distribution in plant tissues, the organization of DF polysaccharides in the cell wall, and the chemical interactions of these polysaccharides with other cell components. Alkaline, acid, chelating, and oxidant/bleach extractions are most often used to obtain DFs. The choice of a chemical method depends on the polysaccharide of interest. If the solution concentration, pH, time, and temperature condition of the chemical method used are extreme, the structure of the polysaccharides obtained will be modified, changing the functionality of the DFs. Novel approaches, including the use of combined methods, seek to reduce this processing severity. (source)


Best Foods Containing Pre-Biotic Fiber (naturally)

  • Unripe (green) bananas
  • Leeks
  • Asparagus
  • Oats
  • Cocoa
  • Apples
  • Jicama
  • Dandelion Greens
  • Yacon Root
  • Onions
  • Garlic



In reality, added fiber is often from unnatural sources, causes blood sugar spikes, gas, and bloating, and is definitely not zero-calorie. Fiber is not necessarily bad, as long as it’s in its purest form (i.e. fresh fruit, veggies, and beans are great sources of fiber….in their natural state! but when you’re eating something that should not naturally have fiber and does, that’s when you should question)

If you found this post helpful, I encourage you to share it on Instagram 


If you want to make your own, here are some protein bars and snacks you can create at home!
– Cookies and Cream Protein Bars

– Lenny and Larry Cookie Remake

– Instant Cookie Dough Bites

White Chocolate Raspberry Cheesecake Protein Bars

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