Nutritional status, metabolic responses to exercise and implications for performance.

Diet can significantly influence exercise performance. Diet alone will not ensure successful performance in sport, but it plays a permissive role in allowing sustained intensive training with limited risk of illness and injury. Diet may also promote adaptations to training by stimulating synthesis and breakdown of the specific proteins that respond to the training stimulus. Protein synthesis and breakdown are both stimulated for some time after exercise, and protein ingestion before, during or immediately after exercise will enhance the fractional synthetic rate. Carbohydrate and fat are key energy substrates during exercise, and acute nutritional manipulation will affect both substrate selection and exercise performance.