The glycemic index of food is a measure of the postprandial glycemic response caused by food, and it refers to the value of the percentage level of glycemic response in the body of a food containing 50 grams of carbohydrates and an equivalent amount of glucose or white bread within a certain period of time (usually 2 hours). The lower the glycemic index, the less the food reacts to the increase of blood sugar. When the glycemic index of a food is below 55, the food can be considered as a food with low glycemic index; when the glycemic index of a food is between 55 and 75, the food can be considered as a food with medium glycemic index; when the glycemic index of a food is above 75, the food can be considered as a food with high glycemic index.