Allulose is a low-calorie sweetener that doesn’t count towards your sugar intake.
This naturally-occurring sugar substitute doesn’t raise your blood sugar levels, making it perfect for low-carb diets like the keto diet.
As a bonus, allulose has health benefits you won’t find in other natural sweeteners. It can improve your insulin sensitivity, increase fat-burning, and may protect your liver.
Read on to learn about the remarkable properties of allulose, how to use it, and how much is safe to consume.
Allulose is a naturally-occurring monosaccharide (simple sugar). It’s about 70% as sweet as table sugar but contributes 90-95% fewer calories[*].
It is found in small amounts along with other carbs in fruits like figs and raisins, as well as in other agricultural products. Researchers first isolated it about 70 years ago.
Other names for allulose include d-allulose, psicose, and d-psicose.
Structurally, allulose is almost identical to fructose, but it has a “flipped” hydroxyl (OH) group. But unlike fructose, allulose keeps your blood sugar stable.
The most exciting thing about allulose is that, according to the FDA, allulose is no longer counted towards total or added sugars for labeling purposes[*].
That’s because allulose doesn’t act like sugar in your body. Let’s find out how it works.
A big hint that allulose isn’t a typical sugar or carbohydrate comes from the FDA labeling decision.
Essentially, the FDA is acknowledging that allulose doesn’t raise your blood sugar. In fact, it doesn’t behave like a typical sugar at all inside your body.
That’s because unlike fructose, which is metabolized by your liver and causes a spike in blood sugar, allulose is absorbed but isn’t metabolized[*][*]. About 70-80% of allulose is excreted in urine[*][*].
But there’s more to allulose than the fact that it doesn’t spike your blood sugar. Studies also point to some promising health benefits.
In a randomized study of healthy people, 5 to 7.5 grams of allulose consumed before a 75-gram sugary drink resulted in lower blood sugar and insulin levels[*].
During a separate clinical study, a mixed group of people — some of whom had relatively mild type 2 diabetes — consumed 5 grams of allulose at meals three times daily[*]. Researchers discovered that the participants had lower blood glucose and that allulose was safe and didn’t cause any side effects.
According to a rat study, allulose may even help protect pancreatic beta-cells, where insulin is made[*]. Since untreated type 2 diabetes leads to beta-cell death, allulose might help slow or prevent the progression of diabetes.
In a study of healthy men and women, a 5-gram dose of allulose followed by a meal resulted in approximately 10% greater fat-burning compared to the control group[*]. The same study also found that their glucose levels were lower and free fatty acid levels higher, which is favorable for burning fat.
A separate 12-week study of overweight people found that daily allulose prevented weight gain, reduced their waist circumference, and caused weight loss[*]. Another large trial conducted in Korea found similar results[*].
An experiment in mice demonstrated that allulose suppresses appetite and causes the release of GLP-1 (glucagon-like peptide 1)[*]. GLP-1 enhances insulin release, improves insulin sensitivity, and reduces hunger[*][*].
Allulose can also modify gene expression to reduce fat accumulation, promote fat-burning, and increase antioxidant levels (in rats)[*].
These unusual properties mean that allulose may be a helpful tool for preventing and even reversing obesity[*].
Because it increases antioxidant levels and enhances your body’s metabolism of sugar and fat, allulose may also prevent inflammation and related issues in your liver[*].
In a study of mice, allulose supplementation reduced fat mass and improved fatty liver associated with obesity[*]. And another rat study found that allulose reduced the activity of enzymes that contribute to liver fat storage[*].
Finally, a separate rat study found that allulose increased liver insulin sensitivity and glycogen content[*].
So, how much allulose should you eat to get some of the benefits?
From the evidence, allulose appears to be very safe.
For example, a 2010 clinical study found that no abnormal effects or medical issues occurred in people who consumed 15 grams per day for twelve weeks[*].
If you consume too much allulose, you might get nauseated or have diarrhea[*]. The upper limit for a single dose is 0.4 grams per kilogram of body weight (that’s about 27 grams, or approximately two tablespoons, for a 150-pound person at a sitting)[*].
The daily upper limit to avoid gastrointestinal side effects is 0.9 grams per kilogram of body weight (or 61 grams per day for a 150-pound person)[*].
Sugar alternatives like allulose can have unpredictable effects on gut bacteria.
But there haven’t been any studies on allulose’s impact on the microbiome. So, while there’s nothing to suggest it’s harmful, you may want to pay extra attention to how your body responds if you’re prone to gut issues or related problems.
If you’re on the ketogenic diet, low to moderate doses of allulose are extremely unlikely to kick you out of ketosis.
That’s because your body absorbs and excretes allulose without ever metabolizing it as sugar. It also seems to enhance fat oxidation and decrease carbohydrate oxidation, both of which are beneficial for ketosis.
However, the best way to know for sure is to test your ketone levels after eating allulose.
The Takeaway: Is Allulose Keto?
For a simple sugar, allulose is as keto as it gets.
It enhances fat oxidation, lowers your blood sugar, may improve your insulin sensitivity, and could even result in weight loss.
Allulose is also very unlikely to kick you out of ketosis, unlike its evil twin fructose.
Because your body only absorbs a tenth to a twentieth of the calories compared to regular sugar, most of the downsides of eating sugar don’t apply.
That said, any type of sweet treat or rewarding yourself with food can perpetuate addictive eating patterns, even if you use sugar substitutes like allulose.
If you’re starting keto right now, the best strategy is to go a few months without treats to reset your preferences, then enjoy them occasionally. Once you get to a place where you can have a healthy relationship with sweet-tasting foods, allulose is a fantastic choice for a sugar substitute.
And if you use a health product or supplement that uses allulose as a sweetener, you might get an extra boost in your results, which is not true of most sugar substitutes.