A longitudinal evaluation of a biopsychosocial model predicting BMI and disordered eating among young adults

This study examined the utility of a biopsychosocial model to explain both higher body mass index (BMI) and disordered eating. The study was designed to examine the predictors of higher BMI and a number of measures of disordered eating (dietary restraint, drive for muscularity, drive for thinness, binge eating, and compensatory behaviour). Young adults (N = 838) recruited from seven countries, grouped into four regions (Europe, North American countries, Australia, Japan), completed an online survey, with each completion being 12 months apart. The survey included assessments of BMI and disordered eating, and a range of biological, psychological and sociocultural factors expected to predict both outcomes. Results revealed unique patterns of association between predictors and BMI as well as different measures of disordered eating in the four geographical regions. The findings identify the specific nature of biopsychosocial factors that predict both higher BMI and different aspects of disordered eating. They also demonstrate that caution needs to be exercised in generalising findings from one country to other countries.