I get people commenting on my appearance a lot (mostly other women at work). I have struggled with severe body dysmorphia for years and only recently have been getting better. Things like:
-You look so tired
-You look like a doll
-You have lost so much weight
All unsolicited and out of context. And usually in a group setting.
I lost ten pounds on a 145 pound frame. I don't look more tired than any of my colleagues. I dress nicely but conservatively. I have never heard anyone comment on anyone else's appearance, so why does it keep happening to me? It sends me to a bad place where I think about my appearance, when I was enjoying just feeling like a normal person.
People feel entitled to a woman's body, and policing it, particularly if she is young. I have noticed a decline in comments like these as I have aged. If these comments are making you uncomfortable, and this is a frequent occurrence from specific people, I would call them out to HR, it's what they are there for.
My looks are definitely a hot topic with the people in my life and I seriously hate it so much. It's hard to do much of anything about it, though. Because if I dress down then I'm being a slob, but if I dress up apparently I'm trying to vie for attention. I'm always too fat or need to eat more. I'm getting older so I should start taking better care of my skin, but on other days I get "you look so young for your age it's creepy". No matter what, it's never enough.
I'm trying to not tie so much of my self esteem with my looks. Best thing to do this is to really focus on other parts of yourself; your educational leveling up, your mental health, experiencing wonderful things in the world by trying out new exciting things to expand your comfort zone, etc.
"wow, I'm not sure how to respond to that" should do it
Genuinely, your health is only the business of you and your healthcare provider, and in my experience, most people know that (especially if you look & feel just fine, alert and energetic compared to everyone else youre meeting in your life.) So I think these womem may be negging you, unfortunately.
Personally I feel that people who genuinely do have concerns back off when I tell them how much better I am functioning at a healthier weight and with added muscle mass. So sharing how you feel better mentally, and perhaps physically (without giving a history of your mental health concerns, since it's none of their business), can help you to sort out the genuine people from the negging ones.
The reality is some people (maybe most) don’t think before they speak. You have the right to tell anyone that what they said made you feel uncomfortable and that comments on your appearance are not welcomed. If they do it again you can go to HR. I’m sick of assholes.