Changes in diet and physical activity affect the body mass index of Chinese adults

OBJECTIVE: To examine the relationship between diet, particularly dietary fat intake, and body mass index (BMI). DESIGN: Prospective study of adults who participated in the 1989 and 1991 China Health and Nutrition Survey. SUBJECTS: 3484 adults aged 20-45 at baseline (1989) survey. MEASUREMENTS: Measurement of dietary intake with replicated 24 h dietary recalls. Anthropometric measurements. Measurements of physical activity, smoking habit and socio-economic factors. RESULTS: Change in fat intake was positively associated with change in BMI in men (beta = 0.00036, P = 0.0001), and change in physical activity level was inversely associated with change in BMI in women (beta = -0.12, P = 0.02). Energy intake, physical activity and major socio-economic factors were related to BMI in cross-sectional analysis. CONCLUSIONS: Diet is becoming an increasingly important determinant of body weight in this population, where fat and energy consumption has been increasing steadily during the past decade.