The carb-counting diet is an eating plan designed to keep blood sugar levels even throughout the day. The diet involves counting the grams of carbohydrates in all the foods you eat. Keeping the amount of carbohydrates consumed at each meal consistent can help prevent fluctuations in blood sugar.The number of carbs someone on the carb-counting diet can eat at each meal or snack varies. A dietitian can help you determine the number that is right for you. It is based on your usual caloric intake, physical activity, lifestyle, and whether you take certain diabetes medications.In general, one serving of a carbohydrate food contains about 15 grams of carbohydrates. For many adults, the plan involves eating three to five carbohydrate servings (or 45 to 75 grams total carbohydrates) at each meal and one or two carbohydrate servings (15 to 30 grams total carbohydrates) at each snack.