Du bist, was du isst

You may be familiar with the old adage 'you are what you eat', but you have to read it in the original German to really get the joke. It was originally coined by the nineteenth century German philosopher Ludwig Andreas Feuerbach. In his essay Concerning Spiritualism and Materialism, Feuerbach wrote:

"Der Mensch ist, was er isst." (The man is what he eats.)

It's a clever pun: in German, 'ist' means 'is', and 'isst' means 'eats'. Feuerbach, a firm atheist, was not trying to give dietary advice, but rather was making a fiercely materialist point about the biological, non-divine status of man.