Effect of exercise on 24-month weight loss maintenance in overweight women.

BACKGROUND: Debate remains regarding the amount of physical activity that will facilitate weight loss maintenance.

METHODS: Between December 1, 1999, and January 31, 2003, 201 overweight and obese women (body mass index [calculated as weight in kilograms divided by height in meters squared], 27 to 40; age range, 21-45 years) with no contraindications to weight loss or physical activity were recruited from a hospital-based weight loss research center. Participants were assigned to 1 of 4 behavioral weight loss intervention groups. They were randomly assigned to groups based on physical activity energy expenditure (1000 vs 2000 kcal/wk) and intensity (moderate vs vigorous). Participants also were told to reduce intake to 1200 to 1500 kcal/d. A combination of in-person conversations and telephone calls were conducted during the 24-month study period.

RESULTS: Weight loss did not differ among the randomized groups at 6 months' (8%-10% of initial body weight) or 24 months' (5% of initial body weight) follow-up. Post-hoc analysis showed that individuals sustaining a loss of 10% or more of initial body weight at 24 months reported performing more physical activity (1835 kcal/wk or 275 min/wk) compared with those sustaining a weight loss of less than 10% of initial body weight (P < .001).

CONCLUSIONS: The addition of 275 mins/wk of physical activity, in combination with a reduction in energy intake, is important in allowing overweight women to sustain a weight loss of more than 10%. Interventions to facilitate this level of physical activity are needed.