I was wondering the same thing..this is what I found. Not sure if this is good or not..you still have to eat it in moderation!

The sugar alcohols commonly found in foods are sorbitol, mannitol, xylitol, isomalt, and hydrogenated starch hydrolysates. Sugar alcohols come from plant products such as fruits and berries. The carbohydrate in these plant products is altered through a chemical process. These sugar substitutes provide somewhat fewer calories than table sugar (sucrose), mainly because they are not well absorbed and may even have a small laxative effect.

Many so-called "dietetic" foods that are labeled "sugar free" or "no sugar added" in fact contain sugar alcohols. People with diabetes MISTAKENLY think that foods labeled as "sugar free" or "no sugar added" will have no effect on their blood glucose. Foods containing these sugar alcohols need to have their calorie and carbohydrate contents accounted for in your overall meal plan, as it is carbohydrate that raises blood glucose levels. Since many people typically overeat "sugar free" or "no sugar added" foods, their blood glucose may be significantly elevated.

I think erythritol is the only sugar alcohol that has no effect on blood sugar. The other types do raise blood sugar to some extent, but not as much as actual sugar. I read somewhere just recently that a good rule of thumb is to count half of the sugar alcohol grams as regular carbs. It's probably not that same exact percentage for all the different kinds of sugar alcohols, but it's just to be safe and to remind you to not go crazy with sugar alcohol-containing snacks! They're not the "free" foods we'd like them to be.

Also, keep in mind that sugar alcohols can have a serious laxative effect on you. My doctor recently increased my metformin dosage to 2000g a day, and I suddenly can't tolerate sugar alcohols at all any more! (Don't know if there's an actual correlation, but the timing coincided) I loved the Russell Stover sugar-free peanut butter cups so much, but just can't eat them any more.