To ask for pithy but classy comeback for SIL?

12 months ago OP was 11 stone down. Now OP is 8.5 stone down so has gained 2.5 stone and thinks SIL is going to notice and comment

Well that's how I read it anyway

This is perfect. It brooks no possible comeback that wouldn't involve SIL admitting to behaving like a first class cowbag.

Don’t engage. Noting you can say will land on her-much better to not say anything. Talk to more interesting people.

If she says “oh you’re looking well” (or some other way to insinuate she thinks you’ve put on weight. Just smile and say “oh thank you”. Nothing further, don’t fill the silence.

then when she says “oh god I’m much a heifer at the minute” or what ever, just change your smile to a slightly sympathetic one and say “oh don’t worry too much about it, you look lovely” extra points if you can pat her on the arm too.

then busy yourself getting a drink or pretend there is someone across the room you need to just quickly talk to.

dont rise to her comments. But also don’t disagree with her, take her ‘compliments’ as if you believe them to be genuine

Oh yeah, then drift away or at least smile vaguely past her

ask Her if she struggles with self image, when she seems puzzled tell her everyone else can see she’s absolutely beautiful and when she protest tell her she should learn to take a compliment.
she may make a (facetious) comment about your weight. If she says you look as though you have lost weight and you have and if you haven’t just smile and say you have not lost weight but you are pleased to learn you give the impression of slimness and thank her.

When she mentions your weighloss, reply with, thank you, I worked hard and I feel great.
She won't be able to ignore it.
Positivity is a much better road to take than a bitchy come back.
Life is too short.
It doesn't sound like you see her often.

I can't understand your post OP.

Do you weigh 8st 7lb atm?

And if you do, why does your SIL comment.

I just talk about weights workouts if anyone gets boring about this subject. Turn it onto how lifting heavier weights is so good for the body as we age. Zzz but true. And how good it makes me feel. Double zzzz.

No point engaging for something so trivial, even if it is irritating. She's not been well brought up, has she?

I always think if someone wants to put you down or make you feel bad about yourself the best response is to completely deny them that satisfaction.
So if she tells you snidely that you look well, the best reaction is to beam and say "Thank you! I feel amazing!" or even "I know! I love my body!"

“Are you feeling like a heifer? Have you considered whether therapy might help with those feelings, I’ve heard it can be very effective for people with your sort of issues”

”Oh, do you? I find as I’ve got more mature that I don’t have that sort of thought process in my head. I’ve come to realize I was always good enough.”

Well done on the weight loss.
Initially I’d laugh to undercut her and demonstrate my confidence. If she persists, “Well ain’t that the truth?” which my aunt always used, shows agreement, is seen as positive and indicates you’re aware of her ironic comments. She’s a bitchy, neurotic, shallow person, isn’t she?

Agree with her self-disparaging comments and tell her you hope she finds some self-discipline.

I've always struggled with my weight. I'm currently 8.5 stone down, up from 11 stone down 12 months ago 😬.

Would someone please explain what this means. My brain doesn't understand.

This is what I've started to do. It's really rather effective and gets it out of my head much quicker.

This is glorious 🙌

This, pick this 😂
I hate it when people say "you look tired" they really mean you look old. She'll love that one

Perfect

She'll often do that disengenous shit where she disparages herself (god, I'm just feeling such a heifer atm) when she knows that my comparative are much worse. It's all done to make me feel shit.

is it? Or she is talking about herself and really couldn't care less about you. Most people don't think about others half as much as you think they do!

Answer 'Oh you don't look that bad.'
Is brilliant

Oh please say this OP? Whilst eyeing her up in a critical manner.

I get this a lot - I’ve also had a large weight change and people love nothing more than talking about it. I usually go with ‘gosh isn’t it boring talking about how big or small our bodies are all the time?? How disappointing it is every time someone elects to talk to me about that instead of something more interesting’ HARD STARE.

You can have some fun with this!

Take every barbed comment on face value as the loveliest, most sincere comment youve ever had.

THANK YOU Suzie you lovely creature!!! Honestly ive received SO many compliments Im actually starting to get quite embarrassed but its such a thrill to be feeling and looking so healthy and strong! Bless you darling!

Every comment she makes to you treat as the biggest compliment. Say, ‘oh thanks, that’s so sweet of you!’.

If she moans about her weight, either give a sympathetic nod, or tell her about a friend of yours that has had success with a personal trainer, or a therapist that has helped them feel good about their body.

When she goes low, you go high.

Passive-aggressive/pithy retorts are not going high. That's are lowering yourself to her level.

Nod to acknowledge she has spoken. Beyond that, I wouldn't respond.

I just came to say well done on your weight loss. 8.5 stone is incredible. Any tips?

It's not pithy or cutting, but if she says anything about her own size "aww, I'm sorry to hear that" / "I'm sorry to hear you feel that way" is fairly teflon. Implicitly accepting her assertion without reference to yourself. Then move the conversation on.

Also Brooks Gibbs has this angle on bullying which might give you something to work with, albeit again not through cutting remarks