Association Between Changes in Body Weight and Fat Weight in Middle Age General Population

Body weight gain in middle age is thought to be mainly attributable to body fat gain. However, the association between the change in body weight and change in fat weight is not fully understood. In this study, we aimed to clarify the association between the changes in body weight and fat weight in a middle-aged general population using a community-based cohort. We studied 3,193 subjects who underwent health check-ups. Fat weight was measured using a TANITA DC-270A body composition analyzer (Tanita Corporation, Tokyo). Good correlation was observed between the changes in body weight and fat weight (Pearson r = 0.88, P < 0.001). Among the study subjects, 408 (13%) were categorized in the weight loss group (weight loss ≥ 5%), 2,442 (76%) in the weight stable group, and 343 (11%) in the weight gain group (weight gain ≥ 5%). The percentage of change in fat weight in relation to the change in body weight was 65% on average in subjects with body weight loss, and 70% on average in those with body weight gain. Good correlation between changes in body weight and fat weight was observed regardless of age, gender, and baseline body mass index. A change in body weight was closely correlated with a change in fat weight among the middle-aged general population. Body weight change in the middle-age population appears to be mainly attributable to the change in fat weight.