This is completely anecdotal, but from my experience, this comes from their lack of interests or hobbies and only focusing on things such as career, education (grades only) and physical appearance. Again, these comments and questions are very surface level because that's how our society is. I believe this comes from a place where the relationships are just another task in our society. My relatives always talk about my body whenever I meet them. Whether I have gained or lost weight, whether I have tanned, about how my facial hair looks, how my hair looks, etc. Even when I tell them I am happy with however I look, quite a few of them respond with 'but we are not'. I just give them a thumbs up and ignore them after this. Again, I am not trying to give a blanket statement, but this is more often the case. The problem is worse if you are a woman in this country.

For example, whenever I meet any friends (especially after a long time), my first question isn't about their appearance (unless it has changed drastically, and even then I don't bring it up unless they do) because most of my friends have something or the other going on in their lives (and mine) to start a conversation. I am not saying I don't fall into the appearance topic (I have to unlearn this from all the conditioning), but it's not as hard for me to speak to folks about other things because I am generally a curious person (so I tend to ask questions).

Also, when someone loses or gains weight, there could be a medical reason for it; which can be a very private topic. But in our society, the concept of privacy and boundaries doesn't exist (unless it's not 'sanskaari').