Abstract

In some ways, economists and physicians make uneasy partners in the great enterprise of health economics. Economists’ language is of constraints, budgets, costs, trade-offs, and optimization, whereas physicians focus on the science and art of healing. However, economists share much in common with evolutionary biologists and anthropologists working in the field of human nutrition. Evolutionary biologists talk of organisms facing hard constraints (“energy budgets”) and, in the case of humans, of the “expense” of running large brains (14.6 watts). The human brain is 1 kg larger than would be expected from another mammal of our size. For example, the “expensive tissue hypothesis” postulates that the metabolic expense of running a large brain must be offset by savings elsewhere, and this trade-off in humans is achieved by having a small gut. This hypothesis can explain a number of unique aspects of human physiology and nutrition that are not shared by other animals. Humans need and search out high-quality food that can be easily digested, in prehistory particularly favoring animal meat sources, starches, and honey, a process going in parallel with the development of cooking. There is no one ideal human diet. The hallmark of being human seems to be our ability to adapt to many habitats—and to be able to combine and process many different foods to create many healthy diets. The universal impulse to cook our food reminds us that some processing of food is an essential element of all healthy diets, but unfortunately the modern Western diet does not appear to be one of them.