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

ABSTRACT Objective 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). Method 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 Results revealed unique patterns of association between predictors and BMI as well as different measures of disordered eating in the four geographical regions. Conclusions 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. Key Points What is already known about this topic: The literature has already identified various aspects of the biopsychosocial model that predicts disordered eating and higher weight. These studies have primarily focused on disordered eating in cross-sectional studies among adolescents. Obesity and disordered eating have been shown to be related What this topic adds: The study identified the biopsychosocial factors that predict higher BMI and disordered eating among young adults over a 12-month period. The study examined all components of the biopsychosocial model in the one study. The study was conducted across seven countries and identified how these relationships vary from one country to another.