My problem with this movie is that the two male leads are so spectacularly unattractive. The whole message is that we shouldn't judge people by their appearances, fat people are good, etc. etc. blah blah blah. Okay, fine, whatever.
But this only seems to apply to the womenfolk. Jack Black is short and pudgy with bulldog features, and Jason Alexander looks like something that's been boiled and painted. Why is their lack of attractiveness never part of the plot? Good Lord, they roam around the movie looking for babes as if they were a couple of Adonises. Both of these distinctly not good-looking guys get pursued by attractive women, and what's more, the squat four-eyes actually turns down his dolly on the grounds that she's got a long toe. (All this is later justified by his inner hurt feeling...awwwww!!)
Another sign that the movie was put together by a couple of cases of arrested development: Rosemary never stops talking about her low self-esteem, can't handle compliments, etc. yet in every second scene she's wearing something short and tight. This way Gwyneth Paltrow gets to prance around in her skimpies, and yet then we're supposed to get a big yuk-yuk when her fat body double is shown falling out of the same outfit.
I would love to see a female director redo this movie using a couple of ugly women as the leads, and then have attractive men pursue them, just as they are. Wait, I guess no one would buy that.
And one final thing: just because Rosemary was fat, they didn't have to show her constantly stuffing her face. It got to the point where she's grabbing half a cake at a time. That was just pointless and mean, and it was way beyond even a juvenile chuckle.