The now-toned "Clueless" star — who went the way of his "Parks and Recreation" costar
Rudd, 46, who also co-wrote the film's screenplay, told People that he had never exercised that diligently for an extended period of time, but it was much easier to stick with the routine than he thought.
"Everything else about my day kind of had to fit in around the workouts. I was going to be held accountable for it, and there was a reason for doing it," he told the mag. "I wasn't just randomly doing this kind of arbitrarily, which would have made it a lot harder."
The "This is 40" alum nixed alcohol and carbs for a year and did lots of "flips and rolls" in his gymnastics-style workouts. He also quipped that he took a page out of "Guardians of the Galaxy" star Chris Pratt's manual on how to bulk up to play a superhero — even though Ant-Man gets his strength when he shrinks down.
"I basically didn't eat anything for about a year," Rudd told Variety. "I took the Chris Pratt approach to training for an action movie: Eliminate anything fun for a year, and then you can play a hero."