Objectives: To determine the effectiveness of a weight-management program with personal counseling by phone or e-mail.
Methods: A randomized controlled trial of a 6-month program comparing two modes of intervention delivery (phone, n = 462; Internet, n = 464) with self-directed materials (control, n = 460), among overweight employees. Change in body weight after 2 years was the main outcome.
Results: Among complete cases, weight loss in the Internet group was 1.2 kg (95% confidence interval [CI], −1.9 to −0.4) and in the phone group 0.8 kg (95% CI, −1.5 to 0.03), compared with the control group. Multiple imputation of missing body weight resulted in comparative weight losses of −0.9 kg (95% CI, −2.0 to 0.3) and −0.4 kg (95% CI, −1.4 to 0.7).
Conclusions: Among complete cases, the Internet intervention showed modest long-term weight loss, but among all participants neither program version was more effective than self-help.