On the left, you will see "Check out my eight-pack, you think I'm healthy and fit, but I am infertile and my bones are weak" Kate. On the right, you will see "Check out my boobs, I look healthy and feminine and my internal state reflects this" Kate.
Getting my period meant I was healthy. And that was the problem. I didn't want to be healthy; I wanted to be skinny. And I wanted to be skinny more than I wanted to be anything else. When I was 11, a friend asked me what superpower I wanted. I told her I wanted to be invisible.