[jkkramer]

It's also important to make a distinction between "the human body evolved to run long distances" and "the human body is well-suited to running and doing it for long distances is good for you". The latter seems like something we can (and should try to) prove now, without relying on the past for evidence. Knowing how our ancestors lived is nice but I'm personally more interested in knowing what's good for me, here, now.