Mark Wahlberg stopped by The Tonight Show with Jimmy Fallon, Thursday, and revealed his intense weight gain transformation for his upcoming film, Stu. Wahlberg says he ate 11,000 calories a day while filming the upcoming movie.

“Unfortunately, I had to consume, for two weeks, 7,000 calories, and then for another two weeks, 11,000 calories. And it was fun for about an hour,” Wahlberg told Fallon. “It’s such a hard, physical thing to do. Losing weight, you just kind of tough it out, you just don’t eat, and exercise. And this, even when you’re full, I would wake up after a meal and have another meal. I was eating every three hours. It was not fun.”

Mark Wahlberg, Stu
Rich Polk / Getty Images

He added that, despite trying to get the movie done for years now, they only had a month to film it: “Once the metabolism starts to slow down, it gets really difficult. I was trying to get this movie made for six years — we only had 30 days to shoot it — and so, I wanted to really make it happen.”

Stu follows the story of Long, a failed boxer who moves to Los Angeles to try a career in acting. A release date for the movie has yet to be announced.