Do Individual, Online Motivational Interviewing Chat Sessions Enhance Weight Loss in a Group-Based, Online Weight Control Program?

Objective: To examine whether the addition of online motivational interviewing (MI) chats to a Web-based, group behavioral obesity treatment program augments weight loss outcomes relative to the Web-based weight control program alone. Methods: Healthy individuals (N = 398, 24% minority) with overweight/obesity were randomized to a 36-session group Internet behavioral weight control treatment (BT) or the same group Internet treatment plus six individual MI chat sessions (BT + MI). Both conditions received weekly synchronous online chat group sessions for 6 months followed by 12 monthly group chats. Participants in both groups received identical behavioral lessons and individualized therapist feedback on progress toward meeting exercise and calorie goals. BT + MI also received six individual MI sessions delivered by a separate MI counselor via Web chat. Weight loss was measured at 6 and 18 months. Results: There were no significant differences in weight loss between BT (-5.5+/-6.0 kg) and BT + MI (-5.1+/-6.3 kg) at 6 months or at 18 months (-3.3+/-7.1 kg vs. -3.5+/-7.7 kg for BT and BT+MI, respectively). Attendance at group chats did not differ between groups, nor did self-monitoring patterns, suggesting comparable engagement in the weight control program in both conditions. Conclusions: Online MI chat sessions were not a viable strategy to enhance Web-based weight control treatment outcomes.