Polyols are sugar-free sweeteners. Polyols are carbohydrates but they are not sugars. 
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. Because they taste good, people can improve the healthfulness of their diets without having to sacrifice the pleasure of eating sweet foods they enjoy.

 Polyols may be a useful alternative sweetener for people with diabetes

• Mannitol - Reduced-calorie sweetener with only 1.6 calories per gram, nonhygroscopic,Provides sweetness with a clean, cool pleasant taste
• Xyletol - Provides One-Third Fewer Calories than Sugar – about 2.4 Calories per Gram, good Taste with no Unpleasant Aftertaste, helps reducing dental caries and plaque formation.