Abstract
The macronutrient needs of active individuals have been extensively studied to determine how their needs may differ from those of sedentary individuals and how the amount and timing of macronutrient intakes can improve health and performance. From this research, macronutrient recommendations for active individuals have been made. We review 3 areas of current research in sport nutrition related to macronutrient metabolism: (1) Does a carbohydrate supplement during intermittent exercise improve performance? (2) Does a carbohydrate-protein supplement during and after endurance exercise improve performance and enhance recovery? (3) Does macronutrient metabolism during exercise differ between males and females? As with endurance exercise, the recommendation for carbohydrate use during intermittent exercise also seems to improve performance. Ingesting a carbohydrate-protein supplement during exercise does not yield performance improvements but may decrease muscle damage. A carbohydrate-protein supplement consumed after running does not consistently confer performance improvements but may improve net muscle protein synthesis. Active individuals should consider consuming a postexercise carbohydrate-protein supplement or meal because it can confer the same benefits as a carbohydrate-only supplement. Recent research on sex differences shows that substrate utilization differs between males and females; however, there is insufficient evidence at this time to alter macronutrient recommendations for active women. When possible, future research needs to include males and females. Finally, research examining how quality of diet, not just quantity of macronutrient intakes, impacts health and performance should be conducted