Empirical evaluation of physical activity recommendations for weight control in women.

PURPOSE Recent recommendations advise 30-60 min of physical activity per day to prevent weight gain and 60-90 min to prevent weight regain. No studies have used objective measures of physical activity to verify these public health recommendations. The purpose of this study was to use objective measures to quantify the amount and intensity of physical activity in a weight-loss-maintainer group and an always-normal-weight group, and, thus,empirically evaluate the recommendations for prevention of weight gain versus regain. METHODS The weight-loss-maintainer group (N = 135) lost >or= 30.6 kg, maintained >or= 10% weight loss for 14.2 yr, and had a BMI of 22.0 kg.m(-2). The always-normal-weight group (N = 102) had a BMI of 21.1 kg.m(-2) and no history of overweight. Accelerometry was used to assess the amount and intensity of physical activity. RESULTS The weight-loss-maintainer group spent significantly more minutes per day than the always-normal-weight group in physical activity (58.6 vs 52.1; P = 0.0001), largely because of more time spent in higher-intensity activities (24.4 vs 16.9; P = 0.02). The majority of individuals in the always-normal-weight group engaged in 30-60 min.d(-1) of physical activity, whereas a greater proportion of individuals in the weight-loss-maintainer group engaged in > 60 min (P = 0.002). CONCLUSIONS Findings support current recommendations that more activity may be needed to prevent weight regain than to prevent weight gain. Including some higher-intensity activity may also be advisable for weight-loss maintenance.