With respect to both physical activity and nutrition, lifestyles of most young Americans have changed dramatically over time. Decades ago, young people often walked miles to attend school, visit friends, or even see a doctor. There was no television to watch, and no Internet to provide hours of visiting without leaving the house. Rather than choosing from an array of pre-packaged and highly processed foods, families tended to cook at home and spent time enjoying meals together. One of the unfortunate results of such lifestyle changes is a sharp rise in obesity, now being identified in a younger and younger population. The problem has reached epidemic proportions. With the increase in childhood and adolescent obesity comes a host of other illnesses and conditions: diabetes mellitus, high blood pressure, high cholesterol and cancer, along with low self-esteem, depression and anxiety. Written for youth and parents, this work covers the causes and effects of the rise in childhood obesity.