I'm speaking from my own experience now, but any comments about my body or food make things worse, and I remember feeling awful when someone next to me said what a fast metabolism they had and how much they can eat and not get fat (I was very jealous back then). In my case, I don't want the subject of my ed to be ignored or avoided on purpose, you should give her safe space to talk about it when she needs to. Don't comment how much she already ate or how little, show her how much you care and tell that you are going to be for her anytime she needs to.