Initial weight loss is the best predictor for success in obesity treatment and sociodemographic liabilities increase risk for drop-out.

OBJECTIVE: To identify pre-treatment factors related to weight loss in obesity treatment.
METHODS: Weight-related and psychological factors were tested in relation to three different weight loss phases: spontaneous weight loss after screening visit (Pre-treatment), weight loss after a preparatory 5-week series of lectures (Step I) and after group treatment lasting two semesters (Step II) in 247 obesity patients.
RESULTS: The strongest factor for predicting weight loss in the Step II treatment was initial Step I weight loss. At least 1kg weight loss in Step I predicted 13% of the variation in Step II weight loss. Spontaneous pre-treatment weight loss after screening and a history of more weight losses were also related to more Step II weight loss. Psychological encumbrances such as eating disorders and mental distress were not related to weight loss, neither were self-reported motivation nor weight locus of control. The overall attrition rate was 63% and associated with lower education, being an immigrant, lack of occupation, fewer previous weight losses and higher body dissatisfaction.
CONCLUSION: Initial weight loss is the most certain factor for predicting treatment outcome. PRACTICE IMPLICATION: A treatment design including an introductory phase with a minimum weight loss criterion for continuing treatment is suggested. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.