If you stop any person on the street and ask them what causes heart disease, you know what their answer will be: butter and eggs, meat and fat. This infamous Diet-Heart Hypothesis was proposed in 1953, and it took scientists all over the world a few decades to prove it wrong. The trouble is that while science was beginning to cast doubt upon its basic tenets, the Diet-Heart Hypothesis was giving rise to a powerful and wealthy political and commercial machine with a vested interest in promoting it—by means of anti-fat and anti-cholesterol propaganda presented relentlessly and with increasing intensity.