Outcomes and mechanisms of change in cognitive-behavioral interventions for weight loss: A meta-analysis of randomized clinical trials

Objectives: To evaluate the efficacy of CBT in relation to weight loss and related psychological components and to analyze the relationship between alleged cognitive mechanisms of change and weight loss. Methods: The studies we considered eligible were the randomized clinical trials which included and reported a quantitative assessment of change in weight and of potential cognitive mechanisms of successful change in weight and comparing at least one active CBT intervention with a control for adults. Results: We included 16 studies (18 contrasts) with a total of 1.663 participants. The pooled ESs in which a CBT-intervention was compared to a control condition for weight loss, was Hedges' g= 0.31 (95% CI 0.04 to 0.58) favoring CBT and for cognitive factors was g = 0.37 (95% CI 0.22 to 0.45). Results indicated a significant association between motivation outcomes ESs (slope= 0.992, 95% CI 0.13 to 1.85, p =0.02) and selfefficacy ESs (slope= 1.59, 95% CI 0.24 to 2.94, p =0.02) and weight outcomes. Discussion: Current evidence suggests that CBT is effective in weight loss. Clinicians will be more effective if they add to their weight loss interventions components for increasing the motivation and self-efficacy of their patients.