The New York Times throws a few jabs at Russell Crowe, Leonardo di Caprio, and Denzel Washington for gaining weight but concludes:

The change in smoking habits may have something to do with it. Possibly, too, the audience has grown more tolerant of weightier men on screen as the society at large has become heavier.

[…]

But a new willingness to cast heavier men “may have happened organically,” Ms. Fasano said, as Hollywood over the last few years has been plagued by what has widely been seen as a shortage of reliably appealing stars.

It’s really hard to see this as anything other than an outright double standard. Crowe and Washington are middle-aged, it’s really hard not to pack on a few pounds as you get older. At the same time, it’s not as though we see a lot of overweight, middle-aged women in sexy leading roles. To the extent that society is becoming more accepting of overweight people, it seems to be limited entirely to men. 

It’s not like we’re seeing a wholesale questioning of established standards of beauty, we simply seem to have accepted that there’s a lower standard for men when it comes to how they look. So really, what’s changed?

— A. Serwer