Attendance and outcome in a work site weight control program: processes and stages of change as process and predictor variables.

This naturalistic study assessed client changes during treatment and identified salient predictors of therapy attendance and outcome. Subjects were assessed on processes and stages of change, self-efficacy, social support, weight history (including expectations, goals, and reasons for losing weight), and demographics at the beginning, middle, and end of a 10-week, behaviorally oriented work site program for weight control. Significant shifts from contemplation to action occurred for clients remaining in treatment. There were also significant modifications in the use of change processes as a result of treatment: counterconditioning, contingency management, stimulus control, interpersonal control, and social liberation increased while medication use, wishful thinking, and minimizing threats decreased. Change processes employed during the early portion of the group treatment were the best predictors of treatment attendance and outcome, superior to self-efficacy, social support, weight history, and demographic variables. The results supported a transtheoretical model that emphasizes dynamic processes and stages as core dimensions for understanding how people change.