Our evolutionary ancestors once possessed the ability to intuit what food their bodies needed, in what proportions, and ate the right things in the proper amounts--effortlessly balanced. When and why did we lose this ability, and how can we get it back? David Raubenheimer and Stephen Simpson answer these questions in a compelling narrative, based upon five "eureka" moments they experienced in the course of their groundbreaking research. The book shares their colorful scientific journey--from the foothills of Cape Town, to the deserts of Australia--culminating in a unifying theory of nutrition that has profound implications for our current epidemic of metabolic diseases and obesity. The authors ultimately offer useful prescriptions to understand the unwanted side effects of fad diets, gain control over one's food environment, and see that delicious and healthy are integral parts of proper eating.