Glycemic Index, Food Exchange Values and Exercise Performance

Abstract

Postprandial blood glucose and insulin responses to feeding depend on the carbohydrate content of the food. The concepts of the Glycemic Index (GI) and Glycemic Load (GL) are relatively new, but there is a growing interest in their use in scientific fields like nutrition or sport science. It is hypothesized that ingestion of carbohydrates with different GI and/or GL values is associated with changes in metabolic responses that can lead to improved exercise performance, and lower risk of developing chronic diseases such as type 2 diabetes mellitus, coronary heart disease, and cancer. Research has shown that a low-GI/rich-carbohydrate meal prior to prolonged exercise positively affects metabolic responses in favor of exercise performance. However, numerous studies have found no relation between different dietary GI and exercise performance, even though some of those have shown differences in metabolic responses during prolonged exercise. A limited number of studies incorporating GL have produced inconsistent results regarding the appropriateness of using this concept to enhance performance. Additional studies elucidating the time of ingestion of different GI foods and the amount of carbohydrate intake in order to enhance performance are warranted. © 2013 Elsevier Inc. All rights reserved.