Not all carbohydrates behave the same way in a person's body. Impact carbs are the carbohydrates that are digested by your body and turned into blood sugar.Some carbs are digested but not turned into glucose (sugar), while others such as fiber are not digested at all and pass through your body as waste. Impact carbs are the carbohydrates that impact blood sugar levels. Dieters and diabetics attempt to avoid spikes in their blood sugar levels as this releases insulin. Insulin is a trigger to store fat and can inhibit weight loss.

Total impact carbs = (fiber + sugar alcohols) minus total grams of carbohydrates

Sometimes called Polyols, these sweeteners are neither sugars, nor alcohols, but they are carbohydrates. They are sugar molecules with hydroxyl, or alcohol groups attached. They are more slowly and incompletely absorbed from the small intestine then sugar, thus producing a much smaller and slower rise in blood sugar and consequently insulin.