Am I right to be offended by this comment from my mum?

[Permanentlydazed]

I was chatting with my mum this evening while we were driving home, I was chatting about the gym tomorrow. She said to me ‘I noticed yesterday you’re starting to look a bit muscly, I don’t like it, it doesn’t look very nice’
I just brushed it off at the time but now thinking about it, I’ve had an eating disorder for the last 2 years, she has been the only person I’ve confided in about it. I feel like I’m just coming out of it and I’m not underweight anymore, working out regularly so I feel I can eat. It was really insensitive and triggering, now I can’t stop thinking/checking to make sure I’m not bigger than I was.
Would you bring this up again or would you just ignore it and try to move on?

What a cow. ED or not, she shouldn't be commenting on your body. It's not hard to see how you ended up with an ED...ignore her! I bet you look strong and healthy. She may even be jealous.

You are definitely okay to be offended by it OP but have you never said anything stupid yourself? I know I have. Sometimes my mouth opens before my brain engages. I cringe afterwards but humans make mistakes.

Fucking hell. Wtf would you say that to someone whose had an ED?

I bet you look amazing, but get some help if you feel it might cause a blip.

Definitely raise it as otherwise I’m sure it will come up again. I think you have to take a hard line as this was pretty shocking to say in general - would you say that to a friend, a partner, a family member, to someone on the street? There are 0 circumstances in which I’d tell someone I didn’t like their body.

Add to that mix an ED and this is all shades of wrong. What about ‘I noticed you said you didn’t like my body looking muscular. I found that hurtful especially when you know what I’ve been through. Unfortunately I can’t tolerate comments about my body - it really can’t happen again. I hope you understand’.

Jesus that's absolutely awful of her. Is she the type of person to apologise if you bring it up, or will she double down with a "well I'm entitled to my opinion" type response? My mum is very much the latter, says hurtful stuff sometimes but just cannot accept any criticism if called out and won't apologise properly. Sometimes I find that doubling down and refusal to apologise after being explicitly told she's hurt my feelings can be more hurtful than the original comment!
I think a response like @pjani has suggested would be good though.

I sympathise with you because my mum can be like this but with any increase in weight. She said to me 3 months post partum that I should make more effort to lose my baby weight 🙄

For some reason, I think mothers can just be like this and not understand the effect it’s having/think somehow they’re being constructive and I would just call her out on it. Hopefully she will realise and be so embarrassed she had such an effect on you that she won’t do it again.