Sugar alcohols are used to add sweetness to food without adding sugar. They have fewer calories than sugar, but more calories than “non-nutritive sweeteners” such as Splenda®, Equal®, Sweet n’ Low®, or Sweet One®.
The name sugar alcohols is a little misleading because these substances are not sugar and not alcohol. They are carbohydrates that have a chemical structure similar to sugar and similar to alcohol – but are neither. The sugar alcohols are lactitol, mannitol, sorbitol, and xylitol - sometimes called polyols.
Sugar alcohols can replace sugar, usually on a one-to-one basis and contain fewer calories than sugar, but remember they are not calorie-free. Sorbitol, mannitol, and xylitol are naturally found in some plant products such as fruits and berries, but they can also be made in a laboratory. Lactitol is made from lactose, the carbohydrate in milk.
Sugar alcohols are often found in “sugar-free” candy, gum, and cookies. It is important to remember that these products still contain calories. Consuming a large amount of polyols (greater than 50 grams of sorbitol per day or greater than 20 grams of mannitol per day) may cause diarrhea. Products with sorbitol and mannitol may have the following statement on the label: "Excess consumption may have a laxative effect."
FDA. Sugar alcohols. Updated 6/2016. Available at accessdata.fda.gov