Background: The development and use of Web-based programs for weight loss is increasing rapidly, yet they have rarely been evaluated using randomized controlled trials (RCTs). Interestingly, most people who attempt weight loss use commercially available programs, yet it is very uncommon for commercial programs to be evaluated independently or rigorously.
Objective: To compare the efficacy of a standard commercial Web-based weight-loss program (basic) versus an enhanced version of this Web program that provided additional personalized e-feedback and contact from the provider (enhanced) versus a wait-list control group (control) on weight outcomes in overweight and obese adults.
Methods: This purely Web-based trial using a closed online user group was an assessor-blinded RCT with participants randomly allocated to the basic or enhanced 12-week Web-based program, based on social cognitive theory, or the control, with body mass index (BMI) as the primary outcome.
Results: We enrolled 309 adults (129/309, 41.8% male, BMI mean 32.3, SD 4 kg/m(2)) with 84.1% (260/309) retention at 12 weeks. Intention-to-treat analysis showed that both intervention groups reduced their BMI compared with the controls (basic: -0.72, SD 1.1 kg/m(2), enhanced: -1.0, SD 1.4, control: 0.15, SD 0.82; P < .001) and lost significant weight (basic: -2.1, SD 3.3 kg, enhanced: -3.0, SD 4.1, control: 0.4, SD 2.3; P < .001) with changes in waist circumference (basic: -2.0, SD 3.5 cm, enhanced: -3.2, SD 4.7, control: 0.5, SD 3.0; P < .001) and waist-to-height ratio (basic: -0.01, SD 0.02, enhanced: -0.02, SD 0.03, control: 0.0, SD 0.02; P < .001), but no differences were observed between the basic and enhanced groups. The addition of personalized e-feedback and contact provided limited additional benefits compared with the basic program.
Conclusions: A commercial Web-based weight-loss program can be efficacious across a range of weight-related outcomes and lifestyle behaviors and achieve clinically important weight loss. Although the provision of additional personalized feedback did not facilitate greater weight loss after 12 weeks, the impact of superior participant retention on longer-term outcomes requires further study. Further research is required to determine the optimal mix of program features that lead to the biggest treatment impact over time.
Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): 12610000197033.