The film’s writer-producer, Jason Hall, has revealed Cooper was constantly eating to bulk up for his role as Navy SEAL Chris Kyle.
“He was eating about every 55 minutes or something like that, and I want to say it was about 8,000 calories a day,” Hall told People.
His fitness regime was just as strict.
“Bradley used his own trainer, who was busting on him. I think he was working out four hours a day for several months,” adds Hall of Cooper’s fitness regimen.
“He was determined to do it naturally, he didn’t want to use any hormones or steroids or anything. He was just very systematic about it and took his trainer with him wherever he went.”
On top of the massive intake of food and gruelling workouts, Cooper also worked with a vocal coach twice a day and spent hours watching footage of Kyle to make sure he nailed his performance of him.
“He managed to find this essence of Chris Kyle,” Hall explains. “This almost spiritual mentality of the man and what drove him. There were moments where they’d get him at a certain angle and you just felt Chris, you felt the essence of Chris. Standing behind the monitors, I’d just get goose bumps rushing up my legs.”