Since the low-carb/ketogenic lifestyle has begun to catch on among the larger health and dieting community, we have become inundated with "new" and "exciting" products.
Some are awesome and provide pretty substantial breakthroughs in various areas of keto cooking.
Others are utter rubbish, but are given a pretty package and labeled "keto" by big corporations looking to cash-in on the trend.
And some of these products fall into what we call a "grey area"; they look keto-friendly, but for one reason or another they have some properties that could be problematic.
Allulose, a newer sweetener on the market, is one such product. While it's technically a monosaccharide (aka, a simple sugar), the slight chemical difference between allulose and other simple sugars, like fructose or glucose, means it does not digest in the same way as regular sugar. Allulose is believed to pass through the digestive tract without absorption into the blood stream, so theoretically you should be able to eat it without a corresponding rise in your blood sugar. Because it is an actual sugar, it possesses a lot of the same qualities of table sugar when it comes to baking and cooking generally, and it doesn't have the notorious "cooling effect" on the backside that most people experience when consuming the keto-approved sugar alcohols, like xylitol or erythritol.
Sounds great, right?
Well, we hope that's the case. However, what potentially puts allulose in the grey area for us is the lack of substantial human studies that could give some guidance or direction.
Relatively speaking, it's a new alternative sweetener; the ability to mass-produce allulose at a reasonable cost is yet to be discovered (which is why it's pretty pricy, even on Amazon, where you can usually get specialty ingredients in bulk for a decent cost), so its availability was pretty limited until fairly recently. Its effects on the human body are only just beginning to be probed and so, while we know it doesn't digest the same way as table sugar, we really don't know much else about it.
What little research that's out there is a mixed bag. Independent testing on rodents has revealed some alarming increases in liver size after allulose consumption. However, when you dig into that study, aside from the potential pitfalls of testing on rodents and generalizing to another species entirely, you will find the amounts of allulose used in the trial were comically absurd, and not in any way representative of how it would be typically used in a human diet, much less in a rodent equivalent.
In other words, they massively overdosed the rats and there was a bad reaction. Will the same liver results occur in a human who might consume a few grams here and there?
Probably not, but we really don't know.
On the flip side, there are some positive studies about its lack of direct effect on both blood glucose and insulin. However, these studies have been criticized for conflicts of interest due to direct funding from the main manufacturer of the sweetener being studied.
That may or may not be a legitimate criticism, however given the history of various food conglomerates paying off their researchers in exchange for glowing reviews and blame-shifting (hello, Big Sugar), it is reasonable to hold off on a hard verdict until we have a more substantial body of research from independent laboratories.
The United States FDA has given it the GRAS (Generally Recognized As Safe) label.
On the other hand, because it doesn't digest regularly and passes through the gut largely unchanged, it is gaining a reputation for causing some of the same gastric distress for which the sugar alcohols are notorious.
Like we said, mixed bag.
When it comes to our official stance, we put allulose in the same category as items like peanuts and sucralose. Both of the latter have some good points that make them technically compliant with a low-carb and ketogenic lifestyle.
They also have some properties that are concerning, and some people are more sensitive to them than others. At this time, or until we have a larger body of research pointing one way or another, we would classify allulose as a personal choice.
It's compliant, but may not be ideal, and keto consumers need to decide where to draw that line for themselves.
If you try it and notice bloating, gastric distress, or any other negative effects, don't use it. If you don't have any side effects and are comfortable using it, that's cool, too.
We always encourage everyone to do what's best for your own body, and the case of allulose is no different.
H/T Mandy Pagano of KetovangelistKitchen.com for the bulk of the content in this explanation.