Diet and training in the week before competition.

For many years athletes have used carbohydrate loading to enhance endurance performance. This practice has been based on findings demonstrating that 1) exercise induced depletion of the muscle glycogen stores followed by the intake of a carbohydrate rich diet, resulted in muscle glycogen stores above normal values and 2) that the pre-exercise muscle glycogen content was the main determinant of the capacity to perform strenuous exercise to exhaustion. Lately it has been speculated whether a period of a high fat diet, followed by carbohydrate loading to restore or increase muscle glycogen levels above normal, would be of further advantage for exercise performance. From the discussed data it emerges, however, that varying periods of fat adaptation followed by a carbohydrate rich diet prior to exercise is of no benefit for exercise performance. Despite an increased fat oxidation and a concomitant decrease in carbohydrate oxidation during submaximal exercise, no benefit in a subsequent time trial appeared. Data suggest that this dietary regimen impairs the ability to utilise carbohydrates.