I should also point out that a lot of people take this a step further than just what they eat.  People actually make changes to turn this into a lifestyle, things like proper sun exposure, physical activity and they way they workout, adequate sleep and the quality of the sleep.  I do try to incorporate most of these into my lifestyle, I've asked my wife for an atlatl for my lat two birthdays and Christmases but no dice.  I haven't gone as far as getting one of 
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