Christian Bale lost 63 pounds for his role in The Machinist where he played a factory worker who is suffering from severe insomnia. He ate only an apple and a can of tuna fish a day. His inspiration was a photo of the withered musician Hank Williams three months before his death. In the film, the weights written on the bathroom wall are Bale’s actual weights. After the film, he spent the next six months gaining 109 pounds for Batman Begins.
These dramatic "live like the character" stories make me laugh. Adrien Brody sold off his stuff and moved to Europe with two bags to pretend to understand what it was like to be a concentration camp survivor. The key ingredient for all of them is missing...the reality of the situation and knowing that it's just all just pretend and going home to palatial digs when it's all done or in Brody's case, just going to an ATM and checking in to the most expensive hotel in Paris when you get tired of roughing it . All of this is just drama on and off the set.