In tenth grade you say to your friend Katie, “Let’s be anorexic.” You are joking, but not really, and she’s looking straight at you and she says, “Okay.” Katie takes to it like a house on fire, but you are weak. You break and eat after dark with shaking fingers in the cold light of the refrigerator. Katie pares her daily intake down to an apple and a can of tuna until she decides she’s enjoying the tuna too much, and then she drinks the juice but leaves the meat. She cuts her lip on the can and it doesn’t heal and doesn’t heal. She drapes across your bed, staring at the ceiling, and works the cut with her tongue while you do homework. You watch her skeleton emerge like a time-lapse video of decay. One day she passes out on her way back from the lunch line and breaks her collarbone against the corner of a…