Compare carbs. Research shows that it is the total amount of carbohydrate of a meal or snack that most affects blood glucose levels, not whether the source of the carbohydrate is starch or sugar. And sugar-free does not mean carbohydrate-free. Compare the total carbohydrate content of a sugar-free food with that of the standard product. If there is a big difference in carbohydrate content between the two foods, you may want to buy the sugar-free food. If there is little difference in the total grams of carbohydrate, choose the one you want based on price and taste.