Obesity has become a common metabolic disease throughout the world. The second edition of Nutrition, Physical Activity, and Health in Early Life analyzes longitudinal and cross-sectional data on the dietary, development, environmental, and functional factors influencing the growth and development of humans in early life stages. New chapters address the role of genetic factors as well as the prevention, consequences, and treatment of obesity. The text compares body mass index, body composition, and the shifts of adiposity rebound on an international scale. The presented approach combines somatic, functional, biochemical, hormonal, and psychological parameters to characterize development.