A quote from a nutritionist in the BBC television series Food on the Brain:
Part of our body today is yesterday’s lunch.
Perhaps because I’d just eaten a slice of Air Canada’s cheese-like pizza, that hit home. The series is well worth a watch if you can find it: they follow three teens with various learning, behaviour and social problems through nutritional testing followed by a dramatic change in diet (i.e. no longer drinking 4 large bottles of soda every day), followed by a “did their change in diet affect their problems” analysis.