By the middle of the 20th century, we had a pretty good understanding of the nutritional requirements for day-to-day good health. Most people in the West had plenty of food, and life expectancy had risen to seven or eight decades. Medical research then began to concentrate on the role of nutrition in the diseases that cut the good life short, mainly heart disease and cancer. And here meat and its strong appeal turned out to have a significant disadvantage: a diet high in meat is associated with a higher risk of developing heart disease and cancer. In our postindustrial life of physical inactivity and essentially unlimited ability to indulge our taste for meat, meat’s otherwise valuable endowment of energy contributes to obesity, which increases the risk of various diseases. The saturated fats typical of meats raise blood cholesterol levels and can contribute to heart disease. And to the extent that meat displaces from our diet the vegetables and fruits that help fight heart disease and cancer, it increases our vulnerability to both.