The carbohydrate food group is the backbone of an athlete's nutritional program. And they also have the greatest potential to stimulate an insulin surge and reactive hypoglycemia. This discrepancy was first noted by diabetes specialists who were amazed to find that simple carbohydrate foods did not always produce the high and short-lived blood glucose responses traditionally attributed to them. The glycemic index was introduced in the early 1980s to tabulate the effects of carbohydrate-rich foods on blood glucose levels. The GI ranks foods on measured blood glucose levels compared to those following a standard food.
Some laboratories usr glucose as a standard while others prefer to use white bread.
What is very clear is that there is no way to predict blood glucose responses from specific foods without these actual measures. Now that we understand the variable effect of different carbohydrates on the level of the blood glucose, we can more rationally advise those who want to control their blood glucose profiles during the day or after meals. Diabetics are a classic example of a population that benefits from tight control of blood glucose and low GI foods. Those with high blood lipid levels may also benefit from a more even blood glucose profile during the day. The glycemic index has also been proposed as a useful tool in weight control as low GI foods have been shown to produce a longer lasting satiated feeling after meals.