Freakonomics: A Rogue Economist Explores the Hidden Side of Everything by Steven D. Levitt and Stephen J. Dubner - William Morrow, 2005

Acne is caused by pizza and diet pepsi?

Here's the best part:

"A few months ago I saw a dermatologist about a different problem. I couldn't resist: What causes acne? I asked. Well, not diet, he said. I knew this was false. And, really, how could you say such a thing without testing hundreds of different diets -- at least? Which no one had. Several years ago I asked my friend Katharine Milton, a Berkeley anthropologist, whether the indigenous people she studies have acne. No, she said, unless they eat foreign food. The anthropologist was right, the doctor was wrong. The situation reminded me of something in an NIH-sponsored online medical encyclopedia: dental malocculsion, it said, "is most often hereditary." Whereas the work of Robert Corruccini, a professor of anthropology at Southern Illinois University, such as this, had convinced me that dental malocculsion is due to soft food."