The glycemic index is a numeric system that was developed to help people with diabetes control their blood sugar. This index rates carbohydrate foods by how much and how fast they raise blood sugar levels. The glycemic index uses numbers to rate each food with 100 being pure glucose (sugar)—the highest number a food can have--and all other foods are rated below this number. The numbers were developed by using a 50 gram amount of a food item—an amount very few people eat in real life. The food is then rated by how much this 50 gram sample raises blood sugar. The numbers for each food are broken down into three categories: High, Medium and Low. 70-100 is considered high, 56-69 is considered medium and 55 -1 is considered low.
Foods with a high glycemic index rating bring a quick and high rise to blood sugar and then quickly crash. This type of reaction is what a person with diabetes is trying to avoid. Foods with a low glycemic index release glucose more slowly and raise blood sugar more steadily than high glycemic index foods. Most fruits, vegetables, and whole grains are low to medium glycemic index foods. Most of the foods that are recommended a person eat from Mypyramid and the Mediterranean diet-- foods high in fiber--are low to medium glycemic index foods.
For more information, visit http://en.wikipedia.org/wiki/Glycemic_index, http://www.mendosa.com/gi.htm, and https://www.health.harvard.edu/newsweek/Glycemic_index_and_glycemic_load_for_100_foods.htm
