Polyols (or polyalcohols), better known as sugar alcohols (nutritionists call them 'sugar replacers') because part of their structure chemically resembles sugar and part resembles alcohol BUT they are sugar-free sweeteners that are NEITHER sugar nor alcohol!

Look for these names: erythritol, hydrogenated starch hydrolysates (including maltitol syrups), isomalt, lactitol, maltitol, mannitol, sorbitol and xylitol.. Also FYI if a product claims it is sugar free it MUST list sugar alcohols etc on the packaging as well.. but the name should be in the ingredient list

They are slowly and incompletely absorbed from the small intestine into the blood.. the part that is absorbed is metabolized by processes that require little or no insulin (most people do not count these carbs). They are lower in calories than regular sugar as well (ie: sugar = 4 per gram; maltitol = 2.1 calories per gram; sorbitol = 2.6 calories per gram)

"Sugar replacers (polyols) provide fewer calories per gram than does sugar, they do not promote tooth decay and they do not cause sudden increases in blood glucose levels... In some people, excessive consumption may cause gastrointestinal symptoms, such as gas or laxative effects"

They are sometimes combined with other alternative sweeteners, such as acesulfame K, aspartame, saccharin and sucralose.. you want the ones combined with sucralose (splenda) or none since we are trying to avoid aspartame/saccharin etc... sometimes combining gives a more pleasant taste.

HTH

information taken from here