Dr. David J. Jenkins and associates at the University of Toronto developed this ranking system in 1981, which measures the effects of carbohydrates on glucose levels. This system compares available carbohydrates gram for gram in individual foods and gives them an evidence based numeric value of post meal glycemic. Carbohydrates are broken down into the bloodstream and how quickly this takes place determines their numeric value on the ranking system. Carbohydrates that digest slowly in the system are given a value lower on the scale. This means that the carbohydrates releases glucose slowly into the bloodstream. A lower ratio suggests that the person will get more out of the food due to its slower digestion and absorption rates. Some food items that fall into this category are: peanuts, grapefruit, spinach, green beans, and lettuce.
Carbohydrates that metabolize much more rapidly in the bloodstream are given a higher glycemic value. Some of these consist of : white bread, watermelon, white rice, and white potatoes. A person will notice a drop in energy levels very quickly after consuming a high glycemic value food. This means that low glycemic foods are best when activity levels are low or you are going to go to bed. Low glycemic foods are best utitlized throughout the day when energy expenditure is usually the greatest. Lower GI foods have a number of benefits: people who have diabetes, reduced risk of heart disease, and can help people lose and control weight. The best solution is to have a balance of proteins, fats, and lower GI foods in your nutritional protocol in order to maintain energy response.