Yale psychologist Kelly Brownell leads this session of his course on food, biology, and policy, part of the Open Yale Courses series that examines why humans eat the way they do. The lecture continues the course's blend of behavioral science, physiology, and public policy, looking at how appetite, taste, and environment interact with the food industry and government regulation to shape eating habits. Brownell draws on research from his own field, the psychology of obesity and food marketing, to explain why simple willpower explanations fail to account for rising rates of diet-related disease. Running just over an hour, the session keeps to a lecture-hall format with Brownell speaking directly to students, occasionally referencing data and policy debates around school lunches, taxation of sugary drinks, and industry lobbying. It sits within a semester-long survey that treats food choice as a problem spanning biology, psychology, and politics rather than a matter of individual discipline alone.