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” energy bar.
Let's Talk About IMO
Isomalto-oligosaccharide (IMO) is a relatively sweet “prebiotic fiber” that has been popping up in more and more energy bars every day. IMO has been coming under increased scrutiny lately and for good reason.
Health or energy bars that claim to have high amounts of protein but very low levels of net or available carbohydrate, (the carbohydrate left over after dietary fiber and sugar alcohols are subtracted out) have become wildly popular in certain segments of the fitness community.
You’ve no doubt seen these so-called “high protein, low carb” bars all over the place. A key ingredient in many of these bars is IMO, which sneaky energy bar manufacturers advertise as a “prebiotic dietary fiber”. Bars made with IMO often include over 15g of IMO. This allows the bar manufacturer to deceivingly claim that their bar contains a high amount of dietary fiber.
Not knowing this, we innocent consumers see this as a win because this gives us a nutrition bar that appears to have a low level of net carbohydrate and relatively low calories with the added benefit of a prebiotic dietary fiber to go along with all that protein. But 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 Sweeter Side of IMO
To say the average American has a sweet tooth would be an understatement.
After all, what good is a bar that's good for you when eating it is like chewing on sawdust? As consumers become increasingly well-informed though, they're ditching the bars containing nasty ingredients like sucralose and aspartame. Energy bar manufacturers, acutely aware of this problem, are scrambling to find alternatives. This is another way IMOs come in handy.
IMO contains fewer calories per gram than natural sugar. It's high in dietary fiber and contains adequate sweetness to make an energy bar palatable. Energy bar manufacturers began using IMOs as a sweetening agent in their products, and unaware of the truth behind what they were really eating, consumers loved them. 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.
But recent research has revealed some troubling aspects of IMOs and their efficacy as a truly natural source of energy. Some have gone so far as to call it the “fraudulent fiber.”
So What's the Big Problem?
For starters, it turns out that IMO syrup isn't really “natural”, as many bar labels claim.
There is no debating that IMO occurs naturally in some foods. However, it is not economically feasible to extract IMO from foods on a large scale. Because of this, commercially-available IMO syrups are enzymatically synthesized from starch. This process converts starch into smaller chains of glucose units that are linked together via chemical bonds. So it is completely incorrect to say that the IMO syrup added to foods is natural.
Next, IMO syrup is not a completely undigestible dietary fiber, as claimed.
Studies using a digestive modeling system and human salivary or hog pancreatic alpha-amylase showed a lack of hydrolysis of IMO, suggesting that it may be a dietary fiber that would largely resist hydrolysis in the small intestine and reach the colon intact. In these studies, under resting conditions, consumption of IMO causes mean serum glucose levels to increase from 109 mg/dL pre-ingestion to a peak of 136 mg/dL at 30 minutes post-ingestion. Serum insulin also rises in parallel with glucose, reaching a peak of 32 μU/mL at 30 min post-IMO ingestion, up from 4.8 μU/mL pre-ingestion. So what’s this mean?
In a nutshell, the majority of the carbohydrate in the IMO syrup used in these bars is, in fact, digested, absorbed, and metabolized.
And, despite industry claims, IMO is definitely not calorie-free.
IMO syrup instead contains about 2.7 to 3.3 calories per gram. So, it would be dead wrong to assume that the carbohydrates from IMO don’t count as available carbohydrates to the body simply because IMO is often referred to as a dietary fiber. It is also misleading for manufacturers to list the entire carbohydrate content of IMO as dietary fiber since the studies you can read here clearly show that this is not the case.
According to this excellent, well-researched article, “IMO syrup carbs ‘don’t count' in the carb content because they are long-chain molecules. Most sugars, such as white table sugar, are short-chain molecules. Short-chain sugars burn up very quickly. They spike your blood sugar and release a flood of insulin from the pancreas. And then, if the sugars aren’t burned, they get stored as body fat.”
Perhaps you're saying to yourself, “I'll simply look at the ingredient list on my energy bar, and if don't see Isomalto-oligosaccharide or IMO, I should be safe.” Well, not quite. Does it list an ingredient called inulin? This is just another fancy word for IMO.
When you have bars like Kion Bar that are naturally sweetened with honey and contain natural sources of fiber like almonds, chia seeds and cocoa nibs, who needs IMO anyway? To put it bluntly, IMO is not a natural fiber and not quite the low-carb friendly sweetener it's cracked up to be. So steer clear of this “fraudulent fiber”, and try your hardest to always go all-natural. It's not easy these days, but all-natural, IMO free energy bars, such as Kion Bar, are out there.