Behavioural and psychological pretreatment predictors of short- and long-term weight loss among women with overweight and obesity.

Abstract

This study aims at identifying behavioural and psychological pretreatment predictors of 12- and 36-month weight loss in women with overweight/obesity enrolled in a behavioural weight management intervention. A sample of 221 women participated in a randomized controlled trial on weight management (n12 month = 184; n36 month = 156). Multiple linear regressions were used to identify pretreatment predictors of successful weight loss, separately for intervention and control groups. Completers-only and baseline observation carried forward analyses were performed. This study is a secondary analysis of data from the 'Promotion of Exercise and Health in Obesity' randomized controlled trial. Fewer weight loss attempts in the last year positively predicted weight loss at 12 months in the intervention group, explaining 6% of the variance. At 36 months, in the intervention group, 20.2% of the variance in weight change was explained by lower eating disinhibition and higher weight-related quality of life in completers-only analyses, while baseline observation carried forward analyses explained only 9.8% of the variance in weight change via higher self-esteem and lower weight loss expectations. In the control group, higher exercise self-efficacy and a more internal weight locus of control predicted weight loss at 36 months, explaining 13.9% of the variance (completers-only analyses). Previous weight loss attempts were identified as the most efficient pretreatment predictor of 12-month weight loss. Eating disinhibition, weight-related quality of life, self-esteem, weight loss expectations, exercise self-efficacy, and weight locus of control seem to be key factors for long-term success. Level I, randomized controlled trial. ClinicalTrials.gov identifier NCT00513084.