Aims and intended learning outcomes This article aims to describe the importance of body weight for health, the causes and consequences of obesity and potential strategies for weight management. After reading this article you should be able to: ■Assess adults and children for overweight or obesity ■Appreciate that obesity is a complex and chronic disease with multi-factorial causes ■Educate patients about the health consequences of obesity ■Describe health benefits that weight loss can bring to overweight people ■Give advice on healthy eating and physical activity for weight management.