The purpose of this study was to investigate a body weight control in athletes. The body composition (under water weighing), physical working capacity (sub-maximal and maximal endurance capacity, muscle strength and vertical jump) and blood constituents of seven female gymnasts (aged 18-21 years) and eight male weight lifters (aged 19-21 years) were measured before and after the diet. The diet period of gymnasts was 35 day, and that of weight lifters was 7 day. The diet program for weight reduction of gymnasts was conducted under the directions of a diet specialist. The averaged daily diet had 1 194 kcal with 54.7 g of protein, 28.5 g of fat and 173.9 g of carbohydrates. The body weight control of weight lifters was conducted to lose weight (n=3), to gain weight (n=2) and to keep weight steady (n=3). The diet program of weight lifters was without any directions of a diet specialist. Before the dieting energy intakes per day was 2238 kcal, 3201 kcal and 2132 kcal for weight-loss, weight-gain and weight-maintenance group, respectively. After the dieting energy intakes per day was 1283 kcal, 2840 kcal and 2004 kcal, respectively. Also protein intakes per day of weight lifters decreased significantly from 88.4±17.6 g to 52.0±23.9 g. After the dieting body weight of gymnasts decreased significantly from 52.11 kg to 48.35 kg, of which difference was composed of 2.99 kg of fat and 0.77 kg of LBM. The body weight of weight lifters decreased 0.31-0.47 kg, and body composition did not change. This results showed that two groups for weight-loss and weight-gain were not successful in weight control. The physical working capacity of gymasts and weight lifters did not show any significant reduction. Most of blood constituents of gymnasts were still in normal ranges in spite of significant changes. Mose of blood constituents of weight lifters did not show any changes. These data indicates that well-regulated diet has an important role in weight control program of female gymnasts, and the diet program of weight lifters illustrates that any guidances of a diet specialist is required for weight control program for athletes
