Efficacy of a weight-loss website based on positive deviance: A randomized trial

Background: Web-based interventions for weight control could promote more-widespread dissemination of weight-loss opportunities; however, they remain limited in effectiveness. Incorporating weight-control practices used by individuals with long-term weight-loss success ("positive deviants") may improve the efficacy of web-based weight control interventions. Purpose: To evaluate the efficacy of AchieveTogether, a web-based weight-loss intervention for adults based on user-generated weight-loss strategies from successful weight losers. Design: In 20092010, participants were randomized to either a 12-week web-based intervention, AchieveTogether, or a wait-list control condition. Setting/participants: 100 overweight or obese adults participated in the study. Intervention: AchieveTogether was designed to help individuals implement weight control practices used by others who successfully lost and maintained weight. Main outcome measures: The primary outcome was change in weight. Secondary outcomes included blood pressure, daily caloric intake, quality of life, and use of weight control practices. ANCOVA, with adjustment for baseline values on outcome measures, was used to assess differences between groups in primary and secondary outcomes. Statistical analyses were conducted in 20102011. Results: Most participants were women (69.7%) and white (90.8%), with a mean age of 50.3 years and baseline BMI of 33.2; 88% completed post-program assessments. Mean weight loss among intervention participants was -1.4 kg (95% CI= -2.2, -0.5), compared with a mean weight gain of 0.6 kg (95% CI= -0.3, 1.4) in control participants (p<0.01). Conclusions: User-generated weight-loss practices from "positive deviants" could promote weight control in web-based interventions; however, further research is needed to improve program efficacy. Trial registration: This study is registered at ClinicalTrials.gov NCT00709501.