Obesity in children and adolescents is a public health problem on the increase and is the most prevalent metabolic and nutritional disorder in developed countries. As a major non-transmissible disease, obesity has taken on epidemic proportions in developed countries and displaced malnutrition and infections as a major cause of deterioration in health and quality of life. Obesity has thus become one of the great health issues of the 21st century. The WHO recently declared obesity to be a new worldwide syndrome as it not only has a high prevalence in developed countries but also in the so-called emerging economies, the "newly westernized" or "Coca-Colanized" countries as in the case of China, Brazil and Eastern European states where obesity exists alongside malnutrition, as well as in under-developed countries where the prevalence is increasing among the better-off segments of the population.