Effect of caloric deficit and dietary manipulation on aerobic and anaerobic exercise

Twelve competitive wrestlers restricted their caloric intake (92 kJ/kg FFW/day) for 7 days, using a high (HC) or normal (NC) carbohydrate diet to determine the acute effect of caloric deficiency on aerobic and anaerobic exercise performance as well as growth hormone (hGH) and insulin-like growth factor 1 (IGF-1) levels. The subjects were tested while on a eucaloric diet and at the end of the dietary restriction. Neither the dietary restriction nor composition had an effect on the ability to complete an 8-minute run at 85% of maximal capacity, but both produced an increased fat utilization during the run. The responses to the Wingate Anaerobic Test indicated that the NC group had a significant reduction in total and mean power output (-7% & -6%, respectively; p less than 0.05), whereas the HC group maintained all power measures. The caloric restriction, regardless of dietary composition, increased the exercise hGH response more for the NC group than the HC group (p less than 0.05). IGF-1 levels were significantly lowered by the diet, but the diet composition had no effect. These results indicate that even during caloric restriction, a high carbohydrate diet better maintains anerobic exercise performance. Furthermore, the composition of the diet appears to have no effect on the resting hGH and IGF-1 responses to caloric deficits. However, carbohydrate composition may have an effect on the gGH response to exercise.