Can someone tell me how to respond to these scenarios?

[flower76]

I never know what the right thing to say is in these situations.
A woman at work looks to have lost weight and looks great, do I say "you look like you have lost weight" ? I think she would like to hear that but at the same time she might think it's rude.
I sometimes feel as though I'm not allowed to comment as I am a slim person.
Also I feel I can't comment when people in the office talk about food/diet even though I find it interesting as I think they kind of exclude me as not understanding what they are doing.

Comment away on food related stuff if you have something to contribute. I am a slight fatso who was a biiiig fatso. Often talked about diet with a colleague who was ripped as he watched his diet for muscle gain wheras I was looking to lose.

I like hearing that I've lost weight but also feel a bit crap when I've put it on as wonder if people who previously complimented me now think I look terrible. Thats just insecurity though. If unsure maybe compliment clothes, ask if something is new and that gives them an open to mention weightloss if they want to discusa it.

To be honest, I'd never comment on someone's weight loss unless I knew the method they'd lost weight. E.g. if they told me weekly they were going to slimming world then I might comment. If I noticed they'd lost weight but they'd not mentioned they were dieting I wouldn't because it could be illness/stress etc.

Say something like "you're looking great / amazing!". It's then not directly focuses on weight loss but is a compliment none the less.

Maybe ask "what are you doing differently?" (Or similar) as snow opener to talk about diet / weight loss/ exercise.

As someone who is very into healthy eating/living, I love talking to slim people about how they do it! It gives me insight into long-term lifestyles of slim people (and an appreciation that mist work at it, rather than being "naturally thin"). Why do you feel excluded? Maybe it's you're friends that are the problem?