At the beginning of the third millennium, a rising prevalence of overweight and obese children and adolescents were seen in developed as well as developing and threshold countries. According to the WHO, overweight or obesity affects one in ten children or adolescents world-wide. This tendency is a dramatic one because childhood obesity is not only an aesthetic problem which may result in social stigmatisation of affected children, but childhood obesity is a multi-system disease with potentially devastating consequences. As with obesity in adults, childhood obesity is acknowledged to be one of the most important risk factors for hypertension and diabetes during childhood and later in life. This book presents current research in the study of childhood obesity, including physical activity promotion programs to thwart childhood obesity; physiological and psychosocial risk factors in childhood obesity; and the ethnic differences in paediatric obesity and metabolic syndrome.