Recent studies and figures illustrate an alarming increase in overweight and obesity. Obese children and adolescents are likely to stay obese into adulthood, which represents a growing medical and social issue.Overweight and obesity are caused by a wide range of different factors. The primary reason for the development of obesity can usually be traced back to an unfavourable lifestyle. Besides genetic, socio-economic and psychological factors, a combination of low physical activity and food containing high levels of fats and sugar are the main reasons for obesity.The way children are raised and how parents act as a role model for their children strongly affect their behaviour as adolescents. Especially children and adolescents from socially disadvantaged families with low income, a low level of education and a migrant background seem to be affected by overweight and obesity. The key factors to avoid overweight and obesity include the prevention of disease and the promotion of health, especially in adequate settings. The childhood and adolescence lay the foundations for health, health consciousness and health-related behaviour. Families, pre-schools and schools represent rather important environments for children and adolescents and are an essential component for preventive and health-promoting measures. For this purpose, a combination of behavioural and environmental preventive measures is strongly recommended.For many years, a variety of international and national programmes and projects have been trying to prevent and combat the obesity epidemic, as described by the World Health Organization (WHO).Overweight and obesity in childhood and adolescence represent a major challenge to society and should be treated as key topic in healthcare policy as well as in the healthcare system.