By some estimates, 25 percent of young people in the United States are either overweight or obese, a figure that has doubled in the last 30 years. In that time, the amount of physical activity in our lives has decreased while our caloric intake has gone up. The U.S. Surgeon General has called the incidence of excessive weight-which extends to all age groups including the elderly-a public health crisis. By presenting both real-life case studies and...