Do you believe in fairies? Unicorns? BMI?

Mathematician Kieth Devlin of Stanford points out that even the CDC engages in junk science occasionally -- and the "Body Mass Index" is his example.

According to this CDC endorsed metric, these people are all overweight: Kobe Bryant, George Clooney, Matt Damon, Johnny Depp, Brad Pitt, Will Smith, and Denzel Washington. Tom Cruise scored even worse, being classified as downright obese, as was Arnold Shwarzenegger when he was a world champion body-builder. With definitions like that, no wonder Americans think of themselves as having an overweightness epidemic. (Using the CDC's BMI measure, 66 percent of adults in the United States are considered overweight or obese.)