Your body converts the carbs that you eat into glucose/blood sugar for use in a wide variety of metabolic processes. This conversion can happen rapidly or slowly depending on the type of carbohydrate food eaten. This rate is known as the Glycemic Index. A higher number means the food is rapidly converted into glucose - a lower number means the food is more slowly converted into glucose. For example, table sugar has a high glycemic index while beans have a low glycemic index.