A. Sugar alcohols such as sorbitol, xylitol and mannitol are sweeteners found in many food products labeled “sugar-free,” “diabetic” or “low-carb.” They are derived from carbohydrates in plant products, but are chemically altered and contain about half the calories of regular sugar. Anastassios G. Pittas, MD, professor of medicine in the Division of Endocrinology, Diabetes & Metabolism at Tufts Medical Center, says, “Sugar alcohols do affect blood glucose levels but less so than sugar. In moderation, they can be consumed by people with pre-diabetes or diabetes.” (Note that sugar alcohols may cause stomach cramps and diarrhea in some people.)