The purpose of this study was to investigate the influence of weight cycling (WC) which accompanied energy intake restriction or exercise in Japanese young non-obese women (study 1), and the effect of habitual exercise practice during three months in weight-cyclers (study 2). 『WC was defined that subjects experienced four times or more weight fluctuation (5% or more change (gain or loss) of body weight per fluctuation) in last one year.』 Past weight fluctuation and a way of weight loss was researched with questionnaire. Twenty-four young non-obese women (BMI: 21.1±1.3) participated in study 1. Subjects were divided into three groups based on a way of weight loss (with energy intake restriction alone [WC-ER: n=7], with exercise [WC-Ex: n=7], no weight fluctuation [Control: n=7]). WC-ER and Control did not have exercise custom in last one year. In study 1, percent body fat was significantly low in WC-Ex (p<0.05). Metabolic parameters in plasma (Total-, LDL-, HDL-cholesterol, TG, Glucose, Insulin, HbA1c and Adiponectin) were not different between groups, but resting energy expenditure (REE) was significantly decreased in WC-ER (3.17±0.29, WC-Ex: 3.60±0.20, Control: 3.54±0.31ml/kg/min, p<0.05). Moreover, REE per lean body mass was also decreased in WC-ER (p<0.05). In study 2 (n=5), REE was significantly increased (pre: 3.10±0.27, post: 3.63±0.21ml/kg/min, p<0.01) after three months though body composition was not changed. These results suggest that WC with exercise has no negative effects, but WC through energy restriction alone decreases REE without changing metabolic parameters in young non-obese women. In addition, habitual exercise practice in weightcyclers increases REE.

DESCENTE SPORTS SCIENCE Vol.31/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE