I have six words for you when ED talk is coming your way:
Pretend you are a brick wall.
I mean that literally, actually. And if you want to, you can go find a brick or similar wall to test this out on for illustration. Yell at it, call it every nasty thing you can think of, cry, threaten to hate it forever, tell it it's making you fat and you hate it, tell it it's killling you by making you eat every single day, tell it it's crazy and has some problem of it's own. Tell it how bitchy it is. By all means, tell it anything and everything you're hearing that makes you second-guess yourself.
Notice it's reaction.
Yeah, your daughter is sick right now. Yeah, she has an eating disorder. The ED runs her reactions, and it runs her MOUTH. It's also a lot bossier to her than you've ever imagined being. The kindest thing you can do for your little girl is to not let her eating disorder be the boss of you too. The safest and most effective thing you can do is let the ED smack talk hit the brick wall.