Bradley Cooper ate 6,000 Calories per day to BUFF UP for his role

To prep for his role as Navy SEAL sniper Chris Kyle in the blockbuster movie American Sniper, Bradley Cooper took his physical transformation very seriously!

Packing on 40 pounds of muscle, Cooper tells Men’s Health he consumed an insane 6,000 calories a day — and had to be force-fed! — while getting into character. “I had to get to the point where I believed I was him,” Cooper, 40, told the fitness magazine. “At 185 pounds, it would’ve been a joke….Chris wasn’t ripped. He wasn’t sinewy. He was just a bear.”

Cooper’s pre-production journey wasn’t all Twinkies and Oreos, either. In order to do the least amount of damage to his body while bulking up, Cooper — under the guidance of trainer Jason Walsh and a personal chef — took in five meals a day, along with energy bars and the pre and post-workout shakes. “It was a real shock to my body. If it’s pizza and cake, that’s one thing. Putting 6,000 calories a day in your body gets old quick,” Cooper said.

His caloric intake was in addition to workouts that included exercises such as Bulgarian split squats and single-leg deadlifts.

Having grown out of a whole wardrobe and worn elastic-waist pants almost daily, the star’s transformation was nothing short of spectacular. Cooper’s trainer Walsh said, “you could see him becoming Chris Kyle. His beard grew, and he just got burly. He looked forward to coming in every day and seeing what he could do.”

As Cooper tells Men’s Health, his temporary transformation will stay with him forever. “I knew this was going to be the way in to playing Chris, and it felt amazing. It’s also nice to know it’s possible to do it naturally, in that amount of time.”