Available Carbohydrate and Glycemic Index Combined in New Data Sets for Managing Glycemia and Diabetes

Available carbohydrate data have long been used as a basis for food exchanges in controlling glycemia, but are not entirely appropriate because the same quantity of available carbohydrate in different foods can induce very different degrees of glycemic response. As an additional aid to food selection the glycemic index (GI) is now being increasingly used in diabetes management. GI is a measure of the glycemic response to the carbohydrate component within a food relative to the response to an equi-carbohydrate portion of a reference food. It is difficult to use in practical food exchange because most foods do not consist solely of carbohydrate, and, being a ratio, GI does not refer directly to food quantity. ilitate the use of available carbohydrate data with GI, two data sets are derived in which GI and available carbohydrate are combined for practical management of glycemia: (1) relative glycemic potency (RGP)—the estimated potential of food to induce glycemia relative to equal weight of glucose—essentially the glycemic index adjusted for the available carbohydrate content of the food; (2) glycemic index adjusted exchange value (EVG)—an estimate of the weight of a food that would give the same glycemic response as 10 g glucose. Using RGP and EVG, food quantities indicated for exchange differ markedly from those based on traditional carbohydrate exchanges, and the ranking of foods according to their likely effect on glycemia is often very different than when based on GI. RGP and EVG are easy to use in food substitution for control of glycemia and can be used to derive quantities, in common standard measures, allowing direct exchange of foods.