It's 2025 and people should really know better then to comment on other people's bodies. Like others I've known people to go through significant weight loss due to grief, cancer, severely disordered eating.. also intentional weight loss and pursuit of fitness. It's none of my business!
But more importantly, for me commenting on someone's weight loss is the equivalent to reminding anyone in earshot how unacceptable fatness is - and most of the commentary on this thread, where people are taking issue with WLI is just another form of fat phobia/ weight discrimination. It fits the narrative that people are fat because they are lazy and or stupid and the only way out of fatness is some sort of cheat or shortcut that somehow bypasses all the hard work "naturally thin" people have put in. This completely ignores that food environment and diet culture drive weight gain, not personal failings. I've always been overweight - I also am clever/fairly highly qualified, driven, successful in my work and relationships. I have always worked very hard - I'm not lazy, but have to deal with that perception on a daily basis.
In case it helps anyone else who has yoyo dieted through their entire lives, or anyone considering WLIs, i'd really recommend listening to some of the Fat Science podcast, lots of info about metabolic disorder and explanations around how dieting doesn't work, but also how dangerous it can be.
It references scientific studies that show almost everyone (like 98% or something) of people who have been in larger bodies will not maintain lower weight through dieting for any period of time because of how your body fights against what it interprets as starvation. She observed test results for hormones related to metabolism for people with obesity were similar to people with anorexia, because of the affect of dieting on the body which is the same whether you are small or big. You're very likely to have damaged your metabolism to a degree that you'll regain weight, and probably end up heavier then where you began. Also noting that staying big is probably more healthy then yoyo dieting, which puts a huge strain on heart etc.
She does endorse medical treatment like WLI but these aren't supposed to be prescribed with diet and exercise, it's not really how they are designed to work, but honestly the number of people taking them to basically stop eating is really alarming, likely doing even more damage to their metabolic systems.
Hopefully as the science becomes better understood some of the societal judgements around fatness will fade, but we've had generations of diet culture and fat phobia so it's probably going to take a while.
One of the most interesting bits of research for me around diet culture and mental health related to the treatment of fat people found that these things cause more negative health outcomes then those caused by being fat. In other words being fat is less bad for you then the outcomes caused by the stigma of being fat/ dealing with being fat. So perhaps we could all consider just leaving people tf alone?!