Impact of addressing reasons for weight loss on behavioral weight-control outcome

Background: One way to improve weight control may be to place greater emphasis on the main reasons why individuals want to lose weight. Purpose: To evaluate the effects of emphasizing physical appearance, health, or both on behavioral weight-control outcome. Design: RCT. Data were collected from 2003 to 2005 and analyzed in 2009. Setting/participants: 203 women aged 18-55 years (M=41.8, SD=9.2) and BMI>27 and <40 (M=34.2, SD=3.7) who rated both appearance and health as important reasons for weight loss, enrolled at a university medical center. Intervention: A 6-month weekly behavioral intervention alone (Standard) was compared to an enhanced focus on physical appearance (Appearance), health benefits of weight loss (Health), or both appearance and health (Combined). The 6-month period of acute intervention was followed by six monthly booster sessions. Main outcome measures: The primary outcome was change in body weight (kg). Additional outcomes included the Multidimensional BodySelf Relations Questionnaire, Medical Outcomes Study Short Form-36, and questions about satisfaction with weight, appearance, and health. Assessments were conducted at 0, 6, 12, and 18 months. Results: Appearance demonstrated significantly greater weight loss compared to Standard at 6 months (p=0.0107). Combined demonstrated greater weight loss compared to Standard at 6 and 12 months (p's=0.0034 and 0.0270, respectively). Although addressing motivators differentially affected satisfaction at 6 months, satisfaction was unrelated to weight outcome over the following year. Conclusions: Behavioral interventions incorporating components with a focus on physical appearance were associated with improved short-term weight loss. The mechanism for this effect is unclear and warrants further study.