Obesity-related beliefs predict weight loss after an 8-week low-calorie diet.

The objective of this study was to examine whether beliefs about the cause, consequences, time line, and control of obesity are predictors of the amount of weight loss after an 8-week, low-calorie diet consisting of meal replacements. Forty-eight women and 18 men, mean age=45.9 (range=23 to 73 years) years and body mass index between 30 and 50 participated in a weight-loss program. Beliefs were measured at baseline by the Obesity Cognition Questionnaire and by an eating behavior self-efficacy scale. Correlational and regression analyses were performed to examine whether beliefs predicted weight change. Changes in body mass index, waist circumference, and blood pressure were significant (P <.001). Less weight reduction was associated with poor self-efficacy (r =-0.34, P <.01) and the beliefs that obesity had a physical origin (r =0.27, P =.04) and was not under behavioral control (r =-0.25, P =.04). Self-efficacy remained a significant predictor in regression analysis. The results suggest that the outcome of dietary interventions may be improved when adjusting beliefs, especially self-efficacy.