You are what you eat is a saying I like. I like it because I don't just apply it to things I eat but I put it on a much more broad perspective to mean that you control everything that makes you you.
In the same way that the food you eat is what your cells are made of, your everyday actions compose who you are as a person and how your life will turn out. So every aspect of your life is a direct result of previous actions that you have taken.
You are what you eat also relates to the people you frequent. The people you are close to put ideas in your head and make you who you are. When you are around a certain group you usually become more like them. They influence you and change your view point.
Just a thought...