My family practice doc/family friend developed this...the pride she had when children's clothes were getting too loose on her was heartbreaking. She developed the mindset that any sort of fat (including breast tissue) was unhealthy and had to be eliminated, and this is from an educated doctor.    It really fucks with your mind, and you could logically know one thing (such as women obviously naturally have breast tissue or not being clinically underweight didn't make you unhealthy (provided you aren't fat, of course)), but split yourself from everyone else and "emotionally know" something entirely different for yourself.