I get the mirror thing but for me it goes further... if I try to think back in the past , not when I was overweight but at the weight I am now I can't seem to view myself at my current weight in my mind. In my mind I still see my overweight self. For example I was standing in the kitchen doing something and if I think back to that moment a few hours later I will replace myself with my former fat self in my head like I don't have an accurate self image