This week’s EconTalk is Gary Taubes talking about how much was decreed by “experts” about our bodies based on very little evidence. His discussion of the complex system known as the human body reminded me of macroeconomics–a complex system where correlation is often mistaken for causation, where omitted variables play a crucial role, where aggregates (such as total cholesterol) often mask more than they illuminate, and where policy recommendations often fail to achieve their purported goals without having anyone challenge the received dogma. The creepiest part is that the early champion of the view that fat is bad for your heart was a man named Keys. Keys relentlessly pushed the idea that eating fat was bad for you despite a remarkable lack of evidence. For this Hayekian, Keys reads a little too much like Keynes, which probably tells you as much about me, alas, as it does about Keys and Keynes. But the parallels between your body and the macroeconomy and the alleged “scientific” understanding of both are very interesting.