Bill O:

In the interview with Bale I mention up-thread, I recall that when he was asked if he would ever lose weight for a role like that again, his response was basically "No." Been there, done that and "He would not want to be known as that actor who loses weight."

Interestingly enough, he turned around and did the same thing for his role in "Rescue Dawn."

I have not seen this flick, but I understand it is very powerful.