The Glycemic index is a measure of how quickly a particular carbohydrate is formed into glucose and enters the body. (bodybuilding.com)
The curve is then made into a percent of the averages of the individual responses to obtain the GI for that particular carbohydrate. (bodybuilding.com)
The process is the following: when you eat a particular carbohydrate, blood sugar levels rise. (fitnessandpower.com)