Abstract
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 < 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 < 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.
Key words
Carbohydrates - growth hormone - IGF-1 - exercise - weight loss
