Motivation and Its Relationship to Adherence to Self-monitoring and Weight Loss in a 16-week Internet Behavioral Weight Loss Intervention

ObjectiveTo examine changes in motivation and the relationship of motivation to adherence to self-monitoring and weight loss in a 16-week Internet behavioral weight-loss intervention.DesignTwo-group randomized design.SettingThis study was conducted over the Internet.ParticipantsSixty-six women, ages 22-65, with a body mass index (BMI) between 25 and 40, and with a home computer with Internet access, participated.InterventionThese data are from an Internet behavioral weight-loss program in which all participants received a face-to-face initial session followed by the 16-week Internet program.Main Outcome MeasuresAdherence to self-monitoring and weight loss were the main outcome measures.AnalysisLinear regression and mediation analysis using the Baron and Kenny method were conducted.ResultsAutonomous motivation increased initially and remained high for those who ultimately achieved a 5% weight loss, but declined over time for participants who did not achieve a 5% weight loss. Autonomous motivation at 4 weeks was a predictor of adherence to self-monitoring and 16-week weight loss. Adherence mediated the relationship between autonomous motivation and weight loss.Conclusions and ImplicationsThese results suggest that autonomous motivation may be a promising intervention target for promoting program procedure adherence and weight loss.