The key to diet seems to be not what you eat, but what you don’t. The American diet is too high in processed foods, sugar, salt, and red meat. Junk food is addictive—it overstimulates the brain’s reward system, which evolved in an era when fats and sweets were hard to come by. Apart from that, the fact is, we just don’t know enough about nutrition to say that there is a single best diet. As a report on the state of nutritional advice at Stanford University noted, “The history of nutrition science is littered with the remains of hypotheses that were once the next big thing.”
