Can we please not talk about my weight

There's this magazine editor who ALWAYS greets me, without fail, everytime we meet each other in functions: "Liz, you're so thin! You lost so much weight!" Every. Single. Time. Even when I've gained weight, or even when I haven't actually lost any. There's also another acquaintance of mine who says the same thing every time we see each other. I'm not sure if they're being sarcastic, but I've given this a lot of thought and have come up with three reasons these people open their interactions with me this way.

1. They're just making idle, safe conversation - in their minds, anyway. Opening a conversation with a compliment is a great way to get things going. I myself do this a lot, but of course I am sincere in my flattery. But I don't just mention ONE compliment every time. I compliment what I like as I see it; I don't have a standard opening line.

2. They want me to also notice that they lost weight, too (even if they haven't). It's subtle prodding for a similar compliment. I've observed that people who mention pounds in a conversation are conscious about it a tad overmuch. I think we're all a little paranoid there but it shouldn't be something you talk about with acquaintances! Weight should be like money - you don't mention it in polite society. (Except when you're blogging about it, obvs.)

3. They honestly think I actually lost weight, because I look kinda fat in most of my photos. I'm not a photogenic person. When other people take pictures of me, I don't even bother to check what it looks like - I know it'll be terrible. I'm top heavy (and sadly not even in the boob department, just in my wide face, squat neck, large shoulders, and fat arms), which means all upper body photos of me make me appear as if I've got an extra 20 pounds on me.

I currently weigh 124 pounds at 5 foot 3. I don't think I'm a fat and/or ugly person. But this healthy self-image is constantly challenged by people who, even if well-meaning, seem to think I was recently very fat. All the time. I mean wtf. 

Do you have a similar problem? Are people always mentioning your weight?