What is allulose, and how is it different from sugar?

Allulose is a rare sugar found in small amounts in figs, raisins, and maple syrup. It tastes like table sugar and browns like it, but the body absorbs most of it and passes it out unchanged, so it delivers roughly 0.4 calories per gram instead of 4.

What is allulose, exactly?

Allulose is D-psicose, an epimer of fructose: the same atoms, with one hydroxyl group flipped. Human metabolism is fussy enough about that detail that the enzymes which break down fructose largely ignore allulose. Most of a dose is absorbed in the small intestine, moves through the bloodstream, and leaves in urine within about a day. Only a small fraction reaches the colon, and very little is burned for energy.

Commercially it's made by enzymatically converting fructose, usually corn-derived. FDA has had no objection to GRAS notices for allulose since the early 2010s and in 2019 accepted 0.4 calories per gram as its labeling energy value. On its own allulose is about 70 percent as sweet as sucrose, which is why it's often blended with monk fruit extract or steviol glycosides to close the gap without adding bulk.

Allulose vs sugar: sweetness, calories, and browning

Sweetener	Sweetness vs. sugar	Calories per gram	In "added sugars" on a US label
Table sugar (sucrose)	1x	4	Yes
Allulose	~0.7x	0.4	No — total carbohydrate only
Erythritol	~0.7x	0.2	No — sugar alcohols line
Xylitol	~1x	2.4	No — sugar alcohols line
Sucralose	~600x	0 as used	No
Aspartame	~200x	4, but used in milligrams	No
Steviol glycosides	200–350x	0 as used	No

The practical difference from other sugar substitutes is that allulose behaves like sugar in a hot pan. It takes part in Maillard browning and caramelizes, so cookies brown and caramel sets the way sucralose and stevia can't. It also depresses the freezing point more than sucrose, which is why it shows up in ice creams that stay scoopable straight out of the freezer.

What it won't do is crystallize, so hard candy and crisp meringue tend to fail. Because it browns faster than sucrose, most recipes need a lower oven temperature or a shorter bake time to avoid over-coloring. Swapping one for one also leaves the result noticeably less sweet — about a third more allulose by volume matches sugar.

Why allulose products can say "0 g added sugars"

FDA's 2019 guidance lets manufacturers leave allulose out of both the Total Sugars and the Added Sugars declarations while still counting it in Total Carbohydrate. A protein bar with 12 grams of allulose shows those grams in the carb count and a flat 0 g on the added sugars line. Nothing is being hidden — the label reflects that allulose isn't metabolized like sucrose. It does mean two bars with identical total carbs can read completely differently on the lines most people scan, so how the added sugars line is calculated is worth understanding before comparing packages.

That gap matters if you log what you eat. An allulose-sweetened bar contributes nothing to a day's added-sugar total in Sugar Tracker, an added-sugar tracking app for iPhone, because the figure being logged comes off the added sugars line rather than the carb count — which is exactly why the label wording matters.

How much allulose is too much

Allulose has a tolerance ceiling, and it's the main reason products don't lean on it harder. The share that isn't absorbed pulls water into the gut and ferments in the colon, which produces gas, bloating, cramping, and loose stools. Dose per sitting matters more than the daily total; small servings spread across a day are usually easier than one large hit.

Single-serving products typically land between 5 and 15 grams, which most adults handle without noticing. Problems appear when someone bakes a full recipe with a cup of allulose or stacks a bar on top of an allulose-sweetened yogurt and a sweetened drink. Individual thresholds vary widely. People generally describe it as gentler than sugar alcohols such as maltitol at equivalent sweetness, but gentler isn't the same as free.

Sucralose, aspartame, and xylitol: what the ADI actually means

Most safety questions about sweeteners get answered with an Acceptable Daily Intake — the amount, in milligrams per kilogram of body weight, a person could consume every day across a lifetime without appreciable risk. Regulators set it far below the highest dose that produced no observed effect in testing, usually with a hundredfold safety margin. An ADI is a conservative ceiling, not the point where harm begins.

Is aspartame bad for you?

In July 2023 the International Agency for Research on Cancer classified aspartame as Group 2B, "possibly carcinogenic to humans" — a limited-evidence category that also holds items like aloe vera extract. The same week, the WHO/FAO joint expert committee on food additives reviewed the evidence and kept its ADI at 40 mg per kg of body weight per day. FDA's ADI is 50 mg/kg, and the agency disagreed with the IARC classification. Reaching either number takes far more diet soda per day than typical consumption. Aspartame also contains phenylalanine, so US labels carry a warning for people with phenylketonuria, and it loses sweetness when heated.

Is sucralose safe?

Within its ADI, regulators say yes. FDA set 5 mg/kg per day; JECFA and EFSA set 15 mg/kg. Sucralose is roughly 600 times sweeter than sugar, so the amount in a packet is tiny — most of the packet is a bulking agent such as maltodextrin, which is why a "zero calorie" packet still declares about a gram of carbohydrate.

Is xylitol safe?

Xylitol is a sugar alcohol, roughly as sweet as sucrose at about 2.4 calories per gram, and JECFA places it in the "ADI not specified" category — the least restrictive designation, used when no numerical limit is judged necessary. The real-world limit is digestive: like other polyols it draws water into the gut and causes loose stools long before any toxicological concern. One hard rule isn't about people at all — xylitol is severely toxic to dogs.

Worth separating from all of this: WHO's 2023 guideline conditionally advises against non-sugar sweeteners for weight control. It covers sucralose, aspartame, and steviol glycosides, and explicitly excludes sugar alcohols and low-calorie sugars, so allulose falls outside its scope. The underlying targets haven't moved either way — WHO recommends keeping free sugars under 10 percent of daily energy, and the American Heart Association suggests no more than 25 g a day for women and 36 g for men.

FAQ

Is allulose a sugar alcohol?

No. Erythritol, xylitol, and maltitol are polyols. Allulose is a monosaccharide — a real sugar — that the body mostly declines to metabolize, which is why it never appears on the sugar alcohols line of a US label. Its grams sit inside total carbohydrate instead.

Does allulose raise blood sugar?

Allulose has little measurable effect on blood glucose or insulin, which is why it turns up in keto and diabetes-oriented products. The rest of the food still counts — the flour in an allulose-sweetened cookie behaves like flour.

Can you bake with allulose like sugar?

Mostly. It browns and caramelizes the way sucrose does, so lower the oven temperature or shorten the bake to avoid over-coloring. Use about a third more by volume to match sweetness. Skip it for hard candy and crisp meringue, which need sugar to crystallize.

Why isn't allulose in European products?

Approval runs country by country. Allulose is GRAS in the US and permitted in several Asian markets, but it hasn't cleared the EU's novel food authorization process, so European and UK manufacturers don't use it.

Is allulose keto-friendly?

It's widely used in keto products and gets subtracted in most net-carb math, since it's excluded from total sugars and barely metabolized. Its grams still appear in total carbohydrate, so a keto bar's carb line can look higher than its practical effect on blood sugar.