What is the relevance of knowing about GI of foods?

Let us see how this index is helpful in prescribing therapeutic diets. You would realize that the dietary GI provides an indication of the rate at which, carbohydrate foods are digested. High and low GI diets may be a better measure for assessing the physiological effects of dietary carbohydrates than the traditional 'simple' and 'complex' carbohydrate definition. It allows ranking of foods from those which give rise to the highest blood glucose and insulin responses (high glycernic food) to those associated with the lowest blood glucose and insulin responses (low GI foods). This index integrates multiple influences on glucose availability and is proposed as a means for prescribing diabetic and energy controlled diets.