While I don’t think it’s valid to comment on anyone’s weight at all, full-stop; I also don’t know how you can assume a relatively thin-looking person (in clothes) isn’t just a fat person trying to get out. I’ve struggled with my weight my whole life, and via clothing & continually fighting the desire to eat/drink/consume/etc I’ve mostly kept it under control … and as a fat person, I feel I’m qualified to comment on fat-people issues, and do find it at least mildly annoying when others have assumed I’m not just because I’ve mostly kept that particular demon at bay.