Obesity is new in human evolutionary history, having become possible at the population level with increased food security. Across the past 60 years, social, economic, and technological changes have altered patterns of life almost everywhere on Earth. In tandem, changes in diet and physical activity patterns have been central to the emergence of obesity among many of the world’s populations, including the developing world. Increasing global rates of obesity are broadly attributed to environments that are obesogenic, against an evolutionary heritage that is maladaptive in these new contexts. Obesity has been studied using genetic, physiological, psychological, behavioral, cultural, environmental, and economic frameworks. Although most obesity research is firmly embedded within disciplinary boundaries, some convergence between genetics, physiology, and eating behavior has taken place recently. This chapter reviews changing patterns and understandings of obesity from these diverse perspectives.
