Christian Bale lost 60 pounds for The Machinist

Because therapy is expensive, but starvation is basically free. To play an insomniac factory worker, Bale whittled himself down to an emaciated 120 pounds using the worst diet known to medical science. He was so incredibly thin that his producers were terrified he would drop dead on set. The craziest part? He gained it all right back a few months later to play Batman.