Analysis of mediation and reciprocal effects of changes in weight, self-esteem, and exercise in a behavioral weight loss treatment

Abstract

Improving the treatment of obesity remains a critical

challenge. Several health behaviour change models, often

based on a social-cognitive framework, have been used to

design weight management interventions (Baranowski et

al., 2003). However, most interventions have only produced

modest weight reductions (Wadden et al., 2002) and socialcognitive

variables have shown limited power to predict

weight outcomes (Palmeira et al., 2007). Other predictors, and possibl alte nati e e planatory models, are needed to better understand the mechanisms by which weight loss

and other obesity treatment-outcomes are brought about

(Baranowski, 2006). Self-esteem is one of these possible

mechanisms, because is commonly reported to change

during the treatment, although these changes are not

necessarily associated with weight loss (Blaine et al., 2007;

Maciejewski et al., 2005). This possibility should be more

evident if the program integrates regular exercise, as it

promotes improvements in subjective well-being (Biddle &

Mutrie, 2001), with possible influences on long-term behavioral adherence (e.g. diet, exercise). Following the reciprocal effects model tenets (Marsh & Craven, 2006), we

expect that the influences between changes in weight, selfesteem

and exercise to be reciprocal and might present one

of the mechanisms by which obesity treatments can be

improved.