Henry Cavill credits his trainer, Mark Twight, for assisting him throughout the process.

Henry Cavill is among the most adored personalities, both on and off-screen. Besides, the actor is also recognized for his godly physique. While he had to sculpt a specific body for roles such as Superman, he has always maintained a muscular and toned body. The actor once shared the challenging conditions he faced while shooting for the film Immortals.
Still from Immortals
In the 2011 fantasy action film Immortals, the actor assumed the role of Theseus, a warrior chosen by the Gods to take on evil forces. Playing the character required Cavill to be extremely fit and maintain a particular physique throughout the shot. To achieve this look, he underwent rigorous training and workouts.

Henry Cavill Went Through Hell While Shooting Immortals

Henry Cavill talked about the challenging conditions and sacrifices he had to make to build eight-pack abs in the film. His look required Cavill to shed body fat and sustain a lean physique consistently throughout the film.
Henry Cavill in Immortals
The actor talked about the challenges of getting in shape and then maintaining it. He said that maintaining a 6% body fat while shooting for hours was a real challenge. Juggling all these demands while staying calm and composed proved to be the actor’s biggest hurdle while filming Immortals.

He said (via IMDB):
“Getting in shape was a tough challenge. It was staying in shape, without going on a killing spree, which was the really difficult thing. At 6% body fat, you are working 14 hours days, doing fight choreography, getting half-hour lunches, having to stay in shape, having to train when you can and not being able to eat much. It’s a real challenge to keep yourself professional and not losing your temper while juggling all the training with it. That was the biggest challenge.”
Cavill is known for his great work ethic and commitment to his roles. So, it doesn’t come as a surprise that he managed to maintain the required physique, even though it wasn’t easy. 

Henry Cavill’s Superman Workout Regime Was Difficult Too

Succeeding Brandon Routh, Henry Cavill stepped into the shoes of Superman in Zack Snyder’s Man of Steel. In the film, the actor showcased a godly physique as a superhero. According to IGN, the actor underwent three stages of workouts to get in that shape.
Henry Cavill’s physique in Man of Steel
The first phase involved the actor focusing on Building mass and weight, consuming 5000 calories daily. Despite his love for food, this was not easy for the actor. Cavill shared that as the first phase concluded, he felt like he was going to explode.

Cavill said (via IGN)
“The program involved three stages. The first was to gain weight/mass. So I spent weeks eating nearly 5000 calories daily while lifting extremely heavy, to grow bigger. I love eating, so this stage was not difficult for me, even though I can understand that some people end up having enough of drinking protein shakes 1000 calories a glass. At the end of this stage, I looked like a swole bodybuilder, and I felt like I was going to explode.”
The second phase involved shedding all the fat and carving out the muscles, focusing on specific body areas. Henry Cavill credits his trainer, Mark Twight, for assisting throughout the process.