Ah, Liz...one of the reasons we all love you so much is your ability to share.....

Seventeen, why you are as you are is a point of deep philosophy, and you have obviously come to the right place for the answer. If you want to change, I'd suggest two things: (1) pick one type of food that isn't good for you (and there are LOTS of places that will tell you that) and cut down on it and (2) whatever kind of exercise you do now, do a little more...if none, do a little.