Randomization was stratified according to sex and was generated in blocks of 3 and 6 with the use of a Web-based program. The research staff who notified participants of their assignment were not involved in the collection of follow-up data.
Participants had an equal chance of being assigned to any one of the three study groups. The theoretical framework for the two active interventions was based on social cognitive theory and incorporated behavioral self-management approaches designed to help participants set weight-related goals, self-monitor weight and weight-related behaviors (exercise and reduced calorie intake), increase self-efficacy and social support, and solve problems. These approaches were modeled on those tested in previous trials.15 (link)–17 (link) Motivational interviewing was the primary approach to interactions with participants. Participants in the two intervention groups were encouraged to lose 5% of their baseline weight within 6 months and to maintain the reduced weight until the end of the study.Table 1 shows the key features of the two intervention groups. (For more information on the interventions, see the protocol and the Supplementary Appendix , available at NEJM.org.)
Participants in both intervention groups were encouraged to log on to the study-specific Web site weekly. The Web site contained learning modules; opportunities for self-monitoring of weight, calorie intake, and exercise; and feedback on progress in these key behaviors. Each participant who was assigned to an active intervention received automated monthly e-mail messages summarizing his or her progress. Automated re-engagement e-mail messages were sent to participants who had not logged on to the Web site in the preceding 7 days.
Weight-loss coaches encouraged participants to complete the learning modules and provided positive reinforcement of key behaviors, with an emphasis on self-monitoring of weight, calorie intake, and exercise. Individual sessions (in person or by telephone) were approximately 20 minutes long; group sessions conducted for the group receiving in-person support typically lasted 90 minutes. Participants in both intervention groups were offered weekly contact with coaches during the first 3 months (nine group sessions and three individual sessions for participants receiving in-person support, and 12 weekly calls for those receiving only remote support). During the next 3 months, participants receiving in-person support were offered three monthly contacts (one group session and two individual sessions), whereas the group receiving only remote support were offered 1 call each month. For the remainder of the study, participants in the group receiving in-person support were offered two monthly contacts (one group session and one individual session, with the latter conducted either in person or by telephone), and the group receiving only remote support continued to be offered monthly calls.
The coaches for the group receiving in-person support were employees of Johns Hopkins University, and the coaches for the group receiving only remote support were employees of Healthways. Coaches were trained before enrollment of the first participant and on a quarterly basis thereafter. The topics covered included behavioral theory and strategies, basic nutritional and exercise guidelines, motivational interviewing techniques, and study procedures, including use of the intervention Web site. To assess fidelity to the protocol and to promote motivational interviewing techniques, a case-management team observed the coaches and provided feedback monthly for the first 3 months of the study and quarterly thereafter.
Participants in the control group met with a weight-loss coach at the time of randomization and, if desired, after the final data-collection visit, at 24 months. They also received brochures and a list of recommended Web sites promoting weight loss.
Participants had an equal chance of being assigned to any one of the three study groups. The theoretical framework for the two active interventions was based on social cognitive theory and incorporated behavioral self-management approaches designed to help participants set weight-related goals, self-monitor weight and weight-related behaviors (exercise and reduced calorie intake), increase self-efficacy and social support, and solve problems. These approaches were modeled on those tested in previous trials.15 (link)–17 (link) Motivational interviewing was the primary approach to interactions with participants. Participants in the two intervention groups were encouraged to lose 5% of their baseline weight within 6 months and to maintain the reduced weight until the end of the study.
Participants in both intervention groups were encouraged to log on to the study-specific Web site weekly. The Web site contained learning modules; opportunities for self-monitoring of weight, calorie intake, and exercise; and feedback on progress in these key behaviors. Each participant who was assigned to an active intervention received automated monthly e-mail messages summarizing his or her progress. Automated re-engagement e-mail messages were sent to participants who had not logged on to the Web site in the preceding 7 days.
Weight-loss coaches encouraged participants to complete the learning modules and provided positive reinforcement of key behaviors, with an emphasis on self-monitoring of weight, calorie intake, and exercise. Individual sessions (in person or by telephone) were approximately 20 minutes long; group sessions conducted for the group receiving in-person support typically lasted 90 minutes. Participants in both intervention groups were offered weekly contact with coaches during the first 3 months (nine group sessions and three individual sessions for participants receiving in-person support, and 12 weekly calls for those receiving only remote support). During the next 3 months, participants receiving in-person support were offered three monthly contacts (one group session and two individual sessions), whereas the group receiving only remote support were offered 1 call each month. For the remainder of the study, participants in the group receiving in-person support were offered two monthly contacts (one group session and one individual session, with the latter conducted either in person or by telephone), and the group receiving only remote support continued to be offered monthly calls.
The coaches for the group receiving in-person support were employees of Johns Hopkins University, and the coaches for the group receiving only remote support were employees of Healthways. Coaches were trained before enrollment of the first participant and on a quarterly basis thereafter. The topics covered included behavioral theory and strategies, basic nutritional and exercise guidelines, motivational interviewing techniques, and study procedures, including use of the intervention Web site. To assess fidelity to the protocol and to promote motivational interviewing techniques, a case-management team observed the coaches and provided feedback monthly for the first 3 months of the study and quarterly thereafter.
Participants in the control group met with a weight-loss coach at the time of randomization and, if desired, after the final data-collection visit, at 24 months. They also received brochures and a list of recommended Web sites promoting weight loss.
