Question: Is there a scientific meaning of 'you are what you eat?'

Robert Woolfson answered on 25 Jun 2013:

You’re not going to turn in to a burger if you only eat burgers for a month. However, your body takes the food you eat and breaks it down into smaller components. These components are then absorbed by the body and used by us as fuel, building blocks for the proteins that we’re made of and so on.

So you are (sort of) part burger, part carrot, part bread………