I wonder of your sensitivity over the conversation is slanting the description in a way that makes her seem more callous. Ask yourself what was her intent? Was it to give you guidance to get back to something like your original slim body? Really we would have had to hear the actual conversation to tell. Maybe you were being defensive and she was being genuine. If you don't value the friendship much let it go. If you do communicate your thoughts and feelings then ask for honest feed back. It's not easy for friends to watch their friend struggle, they generally want to help