childhood obesity has recently become a serious threat to public health. Physical activity seems to be declining and there is some evidence that time spent such as TV watching is increasing and that this may be related to obesity. However, not all children are inactive.The foundation for lifelong good health is laid in childhood. And outside of home life, nothing provides more of an immersive experience for children than the time they spend in school. This means schools have a rich opportunity to improve youth health and tackle obesity at the ideal point in time—before problems take hold.