Forty-seven premenopausal white or black women, aged 20 to 46 years, were initially studied in a normal weight range, defined as a body mass index (BMI) of less than 25. About one half of the group were post-obese after a successful weight loss. All subjects were sedentary and exercised less than once per week. One year later, the women were admitted to a clinical research center for a 4-day period during which their body composition, physical fitness, energy exercise economy, and muscle strength were assessed. Two groups of women were identified, the first consisting of 20 gainers who had gained an average of 9.6 kg and the second of 27 maintainers who had gained an average of .7 kg over the past year. The energy expenditure of activity was 44% higher over time in the maintainers group than in the gainers group,1 indicating that physical inactivity, rather than other factors such as metabolic characteristics or dietary intake, accounted for most of the difference between the two groups.
The authors estimate that in order to match the low weight range of the maintainers group those who gained weight would have to engage in 80 minutes per day of moderate-intensity physical activity such as walking, using the stairs, and gardening. This s
Contact: Elizabeth Horowitz
American Journal of Clinical Nutrition