This installment of Yale's undergraduate course on food examines how eating behavior is shaped by biology, psychology, and public policy together. The lecture continues the course's running inquiry into why humans eat what they eat, covering topics such as the neuroscience of hunger and reward, the marketing tactics of the food industry, and the policy debates around obesity, nutrition labeling, and government regulation of what gets sold and advertised. Discussion draws on real-world cases, including food industry practices and legislative fights over school lunch standards and sugar taxes, to show how scientific findings about appetite and taste collide with economic interests and political lobbying. As with the rest of the series, the class treats food not as a purely personal choice but as a product of biology, culture, and policy working on each other, using data and case studies rather than anecdote to make the argument.