Sugars are considered short-chained carbohydrates (1-2 units) that yield 4 calories per gram. Sugar alcohols consist of a slightly different sugar molecule that does not stimulate an increase in blood glucose thus used in foods/fluids for diabetics. Sugar alcohols such as sorbitol, xylitol and mannitol are found naturally in many plants and fruits. They are now a common ingredient in sports nutrition bars or mixes because they improve taste, and help control blood sugar while sweetening the product with fewer calories (especially when combined with high intensity artificial sweeteners) since sugar alcohols only yield ~2-2.5 calories per gram. The lower calories effect is because not all of this type of sugar is absorbed, thus some passes through the digestive track which is the reason a very small percentage of users may get slight stomach/intestinal discomfort or a laxative effect. Sugar alcohols are perfectly safe and often a healthier alternative to conventional sugars/carbohydrates when consumed in the amounts found bars and mixes.