ABSTRACT
The purpose of the present study is to investigate protein metabolism during rapid weight reduction. Six male boxing players put on a restricted diet of their own accord for two weeks. Body weight changes were observed and a biochemical analysis was made of their urine and blood. The initial body weight of 66.1±3.0kg (mean±SE) decreased to 63.6±3.2 kg after two weeks (P<0.01) . The changes in lean body mass (LBM) by weight reduction were not significant, but the LBM tended to decrease after two weeks. The mean caloric intake was 2, 791±728 kcal before the study and 1, 643±548 kcal after two weeks. The reduction of carbohydrate consumption is much more than that of fat and protein consumption. The 3-Me/Cr in urine increased significantly after two weeks (348.1 ± 37.0 μol/g to 508.1 f 45.6 μmol/g, P<0.01) and the increase of Urea-N/Cr in urine (8.4±0.5mg/mg creatinine to 13.7±1.3mg/mg creatinine, P<0.01) was also significant after two weeks. Urine volume decreased significantly after two weeks (P<0.01) . There was no significant difference in the blood components during the weight reduction period. These results might suggest that rapid weight reduction and massive decrease of carbohydrate intake accelerate protein catabolism.