Glen Powell's diet was at the centre of his transformation for The Running Man

Glen Powell underwent a huge transformation for his role in The Running Man remake - and apparently, diet and nutrition was at the heart of it.

Having lost weight for a previous role, Powell's goal was clear - to gain muscle while staying lean.

"The brief was basically to bulk him up as much as we could," strength and conditioning specialist Tim Blakeley told Men's Health.

"But I had to keep him lean too, which is tricky because muscle gain usually means a calorie surplus, and we couldn’t really do that. Then there were the stunts. It wasn’t just about aesthetics. It was about conditioning, injury prevention and being able to sprint, jump and take hits safely on set."

So what did Powell's plan look like?

Powell had to overhaul his diet for the role (Romain Maurice/Getty Images for OMEGA)

Blakeley put together a diet plan of five meals a day, as well as extras in-between such as protein shakes.

The strength and conditioning expert explained that he worked alongside a chef to create the plan, made up of clean foods and high protein options.

"Nothing complicated. Just clean, absorbable food and high protein," he said.

"A lot of people in film will dry someone out to look leaner, but that wasn’t an option here."

This was thanks, in no small part, to what Blakeley describes as the film's key 'reveal scene', where Powell is seen abseiling down a building in a bath towel.

"He had to perform stunts," he added.

"Dehydration increases the risk of muscle tears."

(Paramount Pictures)

While Powell usually had an egg white and chicken omelette for breakfast, four further meals would follow, focused on high proteins such as chicken, salmon and steak.

While Powell did incorporate carbs into the meals, the amounts were altered each day.

With just four weeks to prepare, the strict plan was said to be at the heart of Powell's transformation.

The movie is adapted from Stephen King's 1982 novel and sees Powell play Ben Richards, a working man trying to save his family in a dystopian world in which only the rich have access to medication.

Richards is balancing losing his factory job with trying to provide medicine for his sick daughter, all the while managing an anger issue.

The film was released in cinemas last month, and Powell has recently spoken about the possibility of appearing in a different type of movie.

When asked by JOE about being the next 007, he recently said: “Bond? Absolutely not.”

Powell in The Running Man (Paramount Pictures)

He was then asked if he would ever consider the role, to which he responded: “Me? Absolutely not.

“No look I’m a huge James Bond fan. As a kid I tried to get people to call me Pierce, because of Pierce Brosnan, I even wrote a James Bond play.

“All my cousins wanted to be James Bond.

“But no, as a James Bond fan, I know a Brit should play him."