Allulose, sugar alcohols and net carbs
Allulose is a sugar that the US FDA lets manufacturers leave out of “Total Sugars” and “Added Sugars” on the Nutrition Facts label [1].
It still has to be included in “Total Carbohydrate”, because the FDA counts carbohydrates by chemical structure, not by how the body handles them [1].
For calories, the same guidance allows 0.4 kcal per gram of allulose instead of the usual 4 kcal per gram for carbohydrate.
What this means when you read a label
A product sweetened with allulose can show a high “Total Carbohydrate” number and a low “Total Sugars” number. The difference is mostly the allulose.
Sugar alcohols are not all the same
Sugar alcohols (polyols) are listed under Total Carbohydrate, often on their own “Sugar Alcohol” line. Many low-carb products subtract all of them to advertise a low net carb number. That overstates the benefit, because several are partly digested: some of each gram is absorbed and used for energy, and some raises blood sugar [2].
| Sweetener | What the body does with it | Effect on blood sugar | Counted here |
|---|---|---|---|
| Allulose | Mostly absorbed but not used for energy; leaves in urine | Very little | Subtracted in full |
| Erythritol | About 90% absorbed, then passed unchanged in urine | Essentially none (glycemic index about 0) | Subtracted in full |
| Xylitol | About half absorbed; the rest fermented in the gut | Low (glycemic index about 13) | Half subtracted |
| Sorbitol, mannitol, isomalt, lactitol | Partly absorbed | Low (glycemic index under 10) | Half subtracted |
| Maltitol | Much of it digested like sugar | Moderate (glycemic index about 35, maltitol syrup higher) | Half subtracted; count more if you watch blood sugar |
| Glycerin (glycerol) | Fully absorbed | Some | Not subtracted |
Glycemic index values are from the same review [2]. Sugar is about 65 on the same scale.
A practical rule: erythritol and allulose are close to zero; treat other sugar alcohols as half a carb; treat maltitol and glycerin as mostly real carbs. If a “keto” bar is sweetened with maltitol, its net carb number is probably too low.
Other things to know
- Your gut. Sugar alcohols that aren’t absorbed are fermented in the large intestine. Sorbitol, maltitol and xylitol cause gas and loose stools for many people above roughly 10–20 g at once. Erythritol is better tolerated because most of it is absorbed first.
- Erythritol and the heart. A 2023 study linked higher blood erythritol with more heart attacks and strokes, and found that erythritol made platelets clot more easily in the lab [3]. It shows a link, not proof that erythritol causes harm, but it is a reason to use sweeteners in dessert amounts rather than all day. Recipes here use small amounts.
- Dogs. Xylitol is poisonous to dogs, even in small amounts [4]. Keep xylitol-sweetened food away from them.
How this site counts it
Net carbs on this site = total carbs − fiber − allulose − erythritol − half of any other sugar alcohols. Allulose is counted at 0.4 kcal per gram and erythritol at 0.2 kcal per gram. Recipes that need a sweetener use allulose or erythritol. See Reading the macros.
Brands differ, and many “monk fruit” or “stevia” blends are mostly erythritol, while some contain sugar or maltodextrin. Check the ingredient list on yours.
General information, not medical advice. If you have a health condition, are pregnant or take medication, check changes with your doctor.
Sources
- [1]FDA, The Declaration of Allulose and Calories from Allulose on Nutrition and Supplement Facts Labels, guidance for industry (2020). https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-declaration-allulose-and-calories-allulose-nutrition-and-supplement-facts-labels
- [2]Livesey G. Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties. Nutr Res Rev. 2003;16(2):163–191. https://doi.org/10.1079/NRR200371
- [3]Witkowski M, et al. The artificial sweetener erythritol and cardiovascular event risk. Nat Med. 2023;29:710–718. https://doi.org/10.1038/s41591-023-02223-9
- [4]FDA, Paws Off Xylitol; It's Dangerous for Dogs. https://www.fda.gov/consumers/consumer-updates/paws-xylitol-its-dangerous-dogs