ABSTRACT: Controversy exists regarding the optimal rate of weight loss for long-term weight management success.This study examined whether gradual initial weight loss was associated with greater long-term weight reduction than rapid initial loss.Groups were drawn from participants in the TOURS trial, which included a sample of middle-aged (mean = 59.3 years) obese women (mean BMI = 36.8) who received a 6-month lifestyle intervention followed by a 1-year extended care program. Participants were encouraged to reduce caloric intake to achieve weight losses of 0.45 kg/week. Groups were categorized as "FAST" (> or =0.68 kg/week, n = 69), "MODERATE" (> or =0.23 and <0.68 kg/week, n = 104), and "SLOW" (<0.23 kg/week, n = 89) based on rate of weight loss during first month of treatment.The FAST, MODERATE, and SLOW groups differed significantly in mean weight changes at 6 months (-13.5, -8.9, and -5.1 kg, respectively, ps < 0.001), and the FAST and SLOW groups differed significantly at 18 months (-10.9, -7.1, and -3.7 kg, respectively, ps < 0.001). No significant group differences were found in weight regain between 6 and 18 months (2.6, 1.8, and 1.3 kg, respectively, ps < 0.9). The FAST and MODERATE groups were 5.1 and 2.7 times more likely to achieve 10% weight losses at 18 months than the SLOW group.Collectively, findings indicate both short- and long-term advantages to fast initial weight loss. Fast weight losers obtained greater weight reduction and long-term maintenance, and were not more susceptible to weight regain than gradual weight losers.