RESUMEN
Obesity during childhood and adolescence is an increasingly common complaint in our daily clinical practice. The increase in its prevalence makes paediatrician worry about this disease, which is now considered an epidemic by the World Health Organisation. Obesity is a complex disease. Its aetiology is not yet clear, due to the multiple factors involved: environment, genetics, behaviour, life style, neuroendocrinology and metabolism. Persistent obesity increases the risk of suffering from diabetes, cardiovascular disease, hypertension, and gallbladder disease. The treatment of obesity is problematic and there are few patients who persist on a long term weight reduction programme. A multidisciplinary approach is therefore required. Paediatricians, dieticians, nurses, psychologists and psychiatrist should intervene in the treatment programme. Dietary changes must combine a decrease in energy intake and an increase in energy expenditure, inculcating both healthy eating habits and lifestyle without interfering in the child's growth and development.