According to an interview Yahoo had with Jake Gyllenhaal's trainer for the boxing film Southpow, here's how he got completely ripped for the role and packed on 45 pounds of muscle like an insane person...
Gyllenhaal was burning so many calories through rigorous workouts that his diet didn’t need to be terribly strict. He did stick to carbs in the morning and protein in the evening.
Claybon started him off with three hours of workouts a day: An hour-and-a-half in the morning and an hour-and-a-half in the evening.
After two months, the workouts got pushed to six hours a day: Three hours of boxing in the morning and three hours of strengthening, conditioning, and cardio at night.
Among the physical feats, the actor would do 1,000 sit-ups in the morning and 1,000 at night.
It took some convincing at first, but Claybon eventually talked Gyllenhaal into the ring with some pros. The actor sparred with real-life fighters roughly six times.
Even when his fight scenes were complete, Gyllenhaal kept training to stay in the mindset and physical shape of a fighter for his acting scenes.
Pretty simple, right? You can read the rest of the interview here and watch the trailer for the flick below. It looks amazing and was written by the dude who created Sons Of Anarchy.