In this chapter, Easter explores the nuanced relationship between human evolution, the modern food environment, and health. He begins by acknowledging the essential nature of food for survival and asserting that the primary challenge throughout most of human history was finding enough to eat. This scarcity led to the development of mechanisms like the scarcity loop, which motivated human ancestors to continuously seek food. However, the nature of food has drastically changed, especially since the 1970s, with the global food system now producing an abundance of highly palatable foods that are rich in sugar, salt, and fat. This shift has turned eating into a key part of the scarcity loop, for modern food is specifically engineered to be irresistible, leading to overconsumption and health issues.

Easter contrasts modern diets with that of the Tsimane, a tribe in Bolivia, who eat a diet rich in natural, unprocessed foods and have remarkably low rates of cardiovascular disease. He details the science of nutrition and outlines the ways in which the introduction of highly processed foods has altered health and led to an increase in obesity and related diseases. Through personal experience and scientific research, Easter demonstrates that human brains, which have evolved to handle scarcity, now struggle with the modern abundance of food.