Ergh, reading that link was a task and a half. It was dripping unpleasantness and self-righteousness.
The mother is very clearly after the appearance side of things. "My son is very handsome" --why is this relevant? Oh, right, it only makes sense in the context that you want a pretty family (that gives status). It reads, "my son is good looking but his girlfriend isn't. THIS IS A PROBLEM SOMEHOW. How unacceptable for him to be with someone who is less than stunning!"
"She's endangering her health as well as hurting her appearance"--why is the appearance mentioned so often? The awful woman injects "oh and her health also, yeah, that" after the appearance most times, but sometimes doesn't even bother pretending that she's worried about the poor girl's health. And 150lb is above average, sure, but not something I'd see a doctor about.
"I hate to see this beautiful girl... risk losing him because she is not taking care of herself." Yep, that's right, in a world where appearances are so ridiculously important, relationships end because someone gains 30lb. The "health issues" from gaining 30lb over 3 years (are there any?) aren't going to end anything. But a shallow person would very easily end a relationship if they felt the other person wasn't pretty enough.
Run, girl! Or stay with a boy who doesn't understand boundaries and has yet to cut the umbilical cord (who tells anyone, let alone their mother, that stuff!??), and be stuck for the rest of your life with his shallow, judgemental woman taking mental notes every time you eat a slice of pizza!