Food is, in shortly word's, that stuff what you eat.
A old german saying say that you are what you eat (»du bist, was du isst«). If you eat rubbish you will become a less good man than you should be. And you're certainly a less good man than you should be, don't forget this.
Therefore, we all most more look and control what we eat.
And this keyword should help us.
(sorry for my bad speak, this is not my native language.)