Self-Monitoring as a Mediator of Weight Loss in the SMART Randomized Clinical Trial

Abstract

Integral components of behavioral weight-loss treatment include self-monitoring of diet and physical activity along with feedback to participants regarding their behaviors. While providing feedback has been associated with weight loss, no studies have examined the impact of feedback frequency on weight loss or the mediating role of self-monitoring adherence in this relationship. This study examined the effect of participant feedback frequency on weight loss and determined if this effect was mediated by adherence to self-monitoring in a behavioral weight-loss trial conducted in the USA. Participants (N = 210) were randomly assigned to one of three self-monitoring methods with either no-daily feedback messages or daily feedback messages: (1) paper diary (PD), no-daily feedback; (2) personal digital assistant (PDA), no-daily feedback; and (3) PDA, daily tailored feedback messages (PDA + FB). The Sobel test via bootstrapping examined the direct effect of feedback frequency on weight loss and the indirect effect through self-monitoring adherence. Receiving daily feedback messages significantly increased participants' self-monitoring adherence. A significant effect of feedback frequency on weight loss was noted; however, after adjusting for self-monitoring adherence, the effect of feedback frequency on weight loss was no longer significant. Feedback frequency had a significant indirect effect on weight loss through self-monitoring adherence. Self-monitoring adherence mediated the effect of feedback frequency on weight loss. Increasing the frequency with which participants receive feedback could enhance self-monitoring adherence, a critical component of behavioral weight-loss treatment.