The glycemic index is a measurement of the impact of a particular food on blood glucose levels. The glycemic load takes it a step further by also including portion sizes in the calculation.
Neither index faired that well in this long study. No association was found for the glycemic load index and body weight, fat percentage or waist circumference. The glycemic index was a good yardstick in sedentary women, but not in active women or any of the men.