Childhood obesity is an urgent public health problem in North America and throughout most of the industrialized world. Diminishing levels of physical activity and the growth of sedentary pursuits may be contributing to the obesity epidemic. The advent of modern technological societies has brought about dramatic changes in lifestyle over the past century. To gain insights into physical activity levels in pre-industrial era societies, researchers have turned to studying religious groups that have resisted the lure of technological change. Children in Old Order Amish and Old Order Mennonite communities of North America have a lifestyle that still involves walking to school and friends' homes, performing chores, caring for farm animals, and active play. Research has shown that Amish and Mennonite children have higher levels of physical activity than modern-living children, despite less participation in organized competitive sports. As a result, Amish and Mennonite children tend to be leaner than their counterparts in contemporary society. Studying non-mainstream cultures can provide a valuable perspective on human behaviors.