This will be brief and it should be more than obvious to anyone who comes here but I want to say it anyway because it's happening again.
Back in 1980, Robert De Niro packed on 60 pounds to play the older, retired Jake LaMotta in Raging Bull. Two things were said, and said often, that irritated the hell out of me as an actor: One, by his detractors, that it was a gimmick. Two, by his supporters, that it was so incredible(!), which is to say that, somehow, packing on pounds made his acting better. How many times have I heard from someone mentioning Raging Bull, "Oh my God! Did you know he gained 60 pounds to play that role?!" Yes, I did know that. Want to know why he was so good? Because he's Robert De Niro! A hundred other actors could've packed on the pounds and sucked.
The same thing is now happening with Christian Bale. He lost an amazing amount of weight for The Machinist back in 2004 and has done it again for The Fighter from last year. Neither of these make his performances excellent, it's his acting talents and skills that do that. The weight loss does, however, show a stunning command of will and discipline within his craft and he's right to be annoyed at anyone claiming it's a gimmick. To wit, you try and lose 70 pounds when you're not even overweight to begin with until you're within millimeters of being able to see your organs by holding a flashlight against your back!
Let's lay it on the line: Priscilla Presley could've lost 70 pounds to play the title character in Sophie's Choice but I can't imagine her performance existing in anywhere near the same hemisphere as Meryl Streep's. In fact, in an indirect way, Streep is kind of associated with this phenomenon. Surely I'm not the only one who's read or heard comments complaining about her constant use of accents, as if that was either pretentious or a gimmick. Gee, sorry she's not lazier as an actor for you.
And on the gimmick side are the folks who seem to take offense at an actor devoted to or maybe even a little obsessed with his craft. What the hell is so wrong with that? I happen to think someone devoted to an art form is a good thing.
So, to check the scorecard one final time, 1) the weight loss/gain isn't a gimmick, it's discipline and devotion to the craft of acting and 2) the performance is measured by the talent and skill of the performer.
Thank you for allowing me this little acting rant. Now, if you'll excuse me, I'm going to go raid the fridge.