8 Movie Roles That Demanded Extreme Physical Changes

Actors can be ridiculously intense about their craft, and we love them for it.

Sometimes, that dedication leads them to change their appearance, typically by adjusting their weight or hair. Sean Astin, for instance, famously bulked up to play Samwise Gamgee in The Lord of the Rings. More recently, Emma Stone shaved her head for Bugonia.

When it comes to weight, the transformations often come with real health risks, raising questions about how far actors should go for their art. Nowadays, talent frequently opts for alternative methods, such as prosthetics or makeup, which are safer.

Here are eight performances where actors pushed their bodies to extremes.

Editor's note: If you or someone you know is struggling with disordered eating, help is available. The National Eating Disorders Association (NEDA) offers support through their helpline at 1-800-931-2237 or by texting "NEDA" to 741741. Additional resources are available at nationaleatingdisorders.org.

Christian Bale, The Machinist

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Christian Bale took on the role of Trevor Reznik, an insomniac factory worker, and practically evaporated.

Bale dropped 62 pounds in four months, reaching 120 pounds. The 6-foot actor wanted to drop even lower, but filmmakers stopped him due to health concerns, according to the DVD commentary.

His diet consisted of roughly 200 calories per day—a can of tuna and an apple, with coffee and water.

After wrapping, he gained weight back to screen test for Batman Begins. Then he went the opposite way for American Hustle, going from 185 to 228 pounds.

Matthew McConaughey, Dallas Buyers Club

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Matthew McConaughey's role in Dallas Buyers Club earned him an Oscar. To portray Ron Woodroof, a man diagnosed with AIDS in the 1980s, McConaughey lost nearly 50 pounds.

Before starting, McConaughey met with Tom Hanks, who had undergone similar transformations for Philadelphia and Cast Away, and worked with a nutritionist, Parade reports.

"I was not torturing myself, I was militant," he told Joe Rogan.

He didn't lie about how it affected his body, along with aging.

"Man, I'm still recovering from that," McConaughey said.

Michael Fassbender, Hunger

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Hunger tells the story of Bobby Sands, the IRA prisoner who led the 1981 hunger strike and died after 66 days without food. To play Sands, Michael Fassbender went on a diet of less than 900 calories a day for 10 weeks, eating just berries, nuts, and sardines on the recommendation of a nutritionist, according to The Telegraph.

The combination of a 900-calorie-a-day diet and exercise, such as skipping, yoga, and walking, resulted in approximately a 42-pound weight loss, with his final weight reported at 127 pounds, according to Men's Journal. During that time, people who saw him thought he had a terminal illness.

"I was so focused, it was unbelievable. I felt I had the answers to so many things. What was also interesting was that my libido left me," Fassbender told Sunday Times.

The film won the Caméra d'Or at Cannes and launched Fassbender's career.

Charlize Theron, Monster

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Charlize Theron's Oscar-winning portrayal of serial killer Aileen Wuornos required Theron to put on 30 pounds. For her, putting on the weight was a way of understanding what Aileen experienced.

"It wasn't about getting fat," she said (per Spliced Wire). "Aileen wasn't fat. Aileen carried scars on her body from her lifestyle, and if I'd gone to make this movie with my body—physically I'm very athletic—I don't know that I would have felt the things Aileen felt with her body."

The transformation included shaving her eyebrows. Producer Clark Peterson recalled the first time he saw Theron in character, initially thinking she was a stand-in for the actor.

"It was only after a while that I realized it was Charlize," he said (via girl.com.au).

At 27, Theron found it easy to shed the weight after filming. However, when she gained nearly 50 pounds for Tully at the age of 43, it took her a year and a half to lose the extra weight. It was a "very long journey," Variety reports. Theron has since stated that she will never again gain significant weight for a role.

Natalie Portman, V for Vendetta

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For V for Vendetta, Portman's character Evey has her head shaved in a pivotal scene, and director James McTeigue decided to do it for real, on set, with three cameras rolling and no room for a second take.

"I was really excited to get to shave my head—it's something I'd wanted to do for a while and now I had a good excuse," Portman told reporters at the Berlin International Film Festival (per Associated Press). "It was nice to shed that level of vanity for a girl."

McTeigue told USA TODAY that when he first met Portman about the role, he had her put her hair behind her head because he wanted to see what she looked like bald. "That was the only conversation we had about it," he said.

The crew rehearsed the scene multiple times, with men from the crew volunteering to have their heads shaved to test it out. When the day came, McTeigue made sure the clippers weren't stuck, and they shaved Portman's head. "She loved it and kept rubbing her head," he said.

Portman later admitted the experience was unusual.

"It's very rare to be experiencing something in real life at the same time as your character, so that was a pretty unusual experience," she told Moviefone Unscripted.

Robert De Niro, Raging Bull

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For Martin Scorsese's Raging Bull, Robert De Niro played boxer Jake LaMotta at different stages of his life.

First, he spent a year training with La Motta, dedicating himself to almost 1,000 rounds of boxing, transforming from 145 pounds to 165. He was good enough by the time production started that he even boxed professionally (albeit anonymously).

Then production paused, and he gained 60 pounds to portray LaMotta during his downfall, according to Vanity Fair.

The performance earned De Niro the Oscar for Best Actor.

Joaquin Phoenix, Joker

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Joaquin Phoenix's unsettling performance in Joker was amplified by his hollow cheeks and prominent spine. He lost more than 50 pounds for the role with a physician's help (per Prevention).

"It's something I've done before, and you work with a doctor regimented and overseen and safe," he told Access Hollywood.

The weight loss began well before production. Later, he told Jimmy Kimmel it was extremely difficult.

"In the beginning, you're exhausted," he said. "You look at a flight of stairs and it takes 30 seconds—you have to talk yourself into it."

Anne Hathaway, Les Misérables

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Anne Hathaway's performance as Fantine comprised a few minutes on screen, but Hathaway still lost around 25 pounds and cut her hair on camera for the role.

She won the Oscar for Best Supporting Actress, but the experience left her reflecting on the cost of such an extreme transformation.

"I'd lost an unhealthy amount of weight in two weeks," Hathaway told People. "I didn't know anything about nutrition. I taxed my body, and my brain bore the brunt of it for a while. I just felt very anxious and very lost at that time."