OP’s saying this about someone she knows really well - that’s what feels blb.
Yeah, her SIL. Not a friend. Someone she's related to, who likes to ruin events, make nasty comments about unattractive girls and try to spoil women's confidence by making them feel like heifers. Do that and people will push back.
Also talking about EDs as “your horrible disorder” is really off.
EDs are horrible. They wouldn't be disorders if they were lovely and fun. It's not a person's fault if they have a disorder but it's not anyone else's fault either, and constantly making shitty comments to make someone feel bad about eating is an attempt to spread that disorder.
Once you realise that what people say is really about them and their issues you don’t take this kind of stuff personally.
That's very enlightened and everything. But given you keep going back to my assertion that people don't generally look as objectively beautiful in their 40s as they do in their 20s, I don't really believe that you could spend all evening with someone wittering on at your elbow about how much you're eating and what a pig it makes you, and be totally zen. It's entirely possible not to take it personally, but still find it rude, obnoxious, joyless and downright irritating.
Edit: Actually I retract that bit about EDs not being anyone else's fault...it's clear from some posts that actually, some EDs are very much caused by another person. What I meant to say was, they are not likely to be the fault of the person now being subjected to endless commentary about how much they eat and how little the other person eats and everything is about how much everyone's eating...you know what I mean.