When an eating disordered person says, “I’m fat” it doesn’t always mean “I’m fat”. Instead they could be trying to say “I’m sad” or “I’m really angry”. Telling a person with an ED “Oh, you’re not fat” isn’t going to work when they aren’t looking to hear that. They may instead be looking for a way to express anxiety, shame, guilt, depression etc through their ED. Saying “I’m fat” isn’t always just a statement, it’s an emotion.