That's true, but I still think it should only be a rule of thumb rather than an ideology. Also, people in the past didn't live very long -- granted it was mostly infectious diseases, but still. Durk Pearson (one of the few people to take the FDA to court over health freedom and win) once said something like "if you only eat naturally, don't expect to live very long". I remember that one of the oldest people who ever lived said she ate a lot of chocolate (two pounds a week) and olive oil; she also smoked, and only quit at 119 -- none of those (even the olive oil) is very natural.