Obesity in adolescence has increased significantly over the past 30-40 years and a recent international comparison study (13 European countries, Israel and the US) showed that the highest prevalence in adolescents was found in the US (12.6% in 13 year old boys, 10.8% in girls; 13.9% in 15 year old boys and 15.1% in 15 year old girls) and the lowest in Lithuania. This increase in adolescence is a public health concern, because most obese adolescents continue their obesity into adulthood with serious risk for chronic disease. Focus should therefore be on prevention programs that increase healthier patterns of lifestyle and physical activity.