Zac Efron “doesn’t know” if he enjoyed working on The Iron Claw.

The 36-year-old actor portrays wrestler Kevin Von Erich in the biographical sports drama and he spent so much time focusing on his physique, he cut out all socializing and having fun, and he is concerned he spent too much time “narrowing [his] world.”

He told The Rake magazine: “I didn’t do any socializing during filming, I was fully committed to the gym.

“Wake up, ice bath, trying to find decent food, then training upwards of two hours per day.

“I was putting a lot into it, all different modalities of training.

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“Feeling that was unique, I don’t know if I was enjoying it or not, it takes you out of a place where you have the ability to socialize with friends or family or travel or have the legs under you to go out and have dinner – you don’t have it in you.

“I sensed that it was narrowing my world to the point that I wasn’t sure whether I was enjoying it or not.

“I can safely say I don’t know whether I was enjoying the process.”

Efron’s determination to be in the right physical condition turned into an “obsession,” but he admitted that helped him get into character.

He explained: “I have always admired physical transformations for a role and I have had a couple of goes at it.

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“For Kevin, I knew that if I was going to do this right and hold my head high, it was going to be the most physically grueling workout and diet regimen I had ever embarked on.

“I started training six months prior to filming. By the middle of the six months, I realized that that obsession with looking as good as possible and that dedication to the work and the food was becoming an obsession for me, and I took that into the role.

“It was a way for me to become Kevin in a way that I hadn’t anticipated.

“We were both ultimately preparing for roles, as wrestling is a performance too.”

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