It happened to my mom. She eats anything and everything that she wants, and cannot top 100 lbs. (She is 5’7″). Rachel, do NOT wish for something like this!! My mom is quite utterly tired of people coming up to her and saying, “You’ve lost so much weight, dear. Are you ill???” She has developed a response for such folks that shut them up, immediately. : ) Anyway, from what I’ve read, there are no rules with this disease. Probabilities maybe, but no “rules”.