Content Warning: This post discusses restrictive and extreme eating habits, as well as body image issues and depression.When a well-known actor undergoes a physical transformation for a role, it pretty much always becomes a massive topic of discussion, with the biggest question often being: “How did they do it?”Over the years, we’ve seen some pretty wild transformations in instances of both bulking up and slimming down. And the lengths that stars go to achieve the onscreen results are sometimes so extreme — and potentially dangerous — that they intentionally never reveal what they did or exactly how much they lost.However, a number of actors who’ve drastically changed their bodies for movie roles have detailed their strict regimens — more often than not, with the intention of emphasizing how truly miserable and inadvisable it is.

Before we get into it, let’s first make it very clear that extreme dieting can be incredibly dangerous. The majority of these celebs will have had guidance from a professional while undergoing their transformations, and these regimens are not to be replicated. If you or someone you know needs support, you can find resources here.

Without further ado, here’s a list of very dedicated stars who’ve gone to huge extremes for their art. Prepare yourself, because it’s a lot to take in.

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When you think about people looking super ripped in movies, Zac’s Baywatch body is undoubtedly up there. However, the physique came at a price. During a 2022 interview with Men’s Health, Zac got real about how his extreme diet and exercise regimen — which involved waking up at 4:00 a.m. every day to train and taking “powerful diuretics” to look extra lean — actually damaged his health on a much deeper level.

“That Baywatch look, I don’t know if that’s really attainable. There’s just too little water in the skin. Like, it’s fake; it looks CGI’d,” he said. “I started to develop insomnia and I fell into a pretty bad depression, for a long time. Something about that experience burned me out. I had a really hard time recentering. Ultimately they chalked it up to taking way too many diuretics for way too long, and it messed something up.”

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It’s no secret that Austin seriously pushed himself to play the King of Rock and Roll. However, away from the mental dedication he showed — and that memorable voice transformation — Austin also went to extreme measures to gain weight to play the older version of Elvis. “I would go get two dozen doughnuts and eat them all. I really started to pack on some pounds,” he said on Variety’s Awards Circuit podcast in 2023, admitting that he felt “awful.” Austin also said he took inspiration from Ryan Gosling’s Lovely Bones transformation by drinking “microwaved Häagen-Dazs” ice cream. But more on that later.

3. Rosamund Pike — Gone Girl (2014)

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If you’ve seen Gone Girl, you’ll already know how brilliantly terrifying Rosamund is as the villainous Amy Dunne. So just wait until you hear that she lost and gained about 14 pounds “three times over” during filming to perfect Amy’s various transformations in the story. “They scheduled around it, so I had two weeks each time for each fluctuation. It was quite intense,” Rosamund told Vulture in 2014. “It was like turning your body into a chemistry lab, and I couldn’t escape it.”

She trained with a boxer, Holly Lawson, who later broke down exactly what they did. For the weight gain weeks, it was all about lifting super heavy, eating lots of “good fats,” and then tons of carb-heavy meals in the last days before shooting. For the weight-loss cycles, she ate a ton of leafy greens, drank loads of alkaline water, and did high-intensity cardio sessions up to four hours a day, including a daily five mile run.

It was very extreme, and not something Rosamund would recommend. “To a certain extent, my body cooperated, but I don’t know how good it is for you,” she told Vulture. “It’s probably better to be gaining weight steadily over a long period of time.”

4. Beyoncé — Dreamgirls (2006)

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For her role in Dreamgirls, Bey said she lost 20 pounds in two weeks by doing something called the Master Cleanse. The cleanse — ironically sometimes called the Lemonade Diet — involves forgoing solid food for two weeks, and instead drinking a concoction of lemon juice, cayenne pepper, and maple syrup. The Master Cleanse has been criticized widely, and it’s fair to say that Beyoncé didn’t find it all that enjoyable either. “I was very hungry; therefore, I was evil,” she told Ellen DeGeneres. “When we wrapped the movie…I ate a whole dozen of Krispy Kreme donuts.”

5. Christian Bale — The Machinist (2004)

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If there’s one person in Hollywood who knows all about a physical transformation, it’s our guy Christian. But it’s safe to say that his extreme weight loss for The Machinist was on a totally different level. Each day, he’d only have a cup of black coffee, a single apple, and a tin of tuna to round it off. “I came up with the absolutely brilliant method of just smoking cigarettes and drinking whiskey to lose weight,” he previously said.Notably, Christian’s weight loss became so extreme that the film’s producers had to step in and ask him to stop and consider his health. More than two decades later, I don’t think it’s something he’ll ever be doing again. “I’ve become a little bit more boring now, because I’m older and I feel like if I keep doing what I’ve done in the past I’m going to die. So, I’d prefer not to die,” he said in 2019.

6. Chris Hemsworth — In The Heart of the Sea (2015)

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Chris is probably best recognized for his bulked-up Thor physique, but, for In The Heart of the Sea in 2015, the Aussie had to do a complete 180 on his diet to lose 33 pounds in four weeks. Eating about 500 calories a day, Chris survived on boiled eggs, salads, and “nothing much” else, leading him to “a pretty moody existence and inconsistent emotions.” “You play all sorts of games – if I eat this, maybe I don’t eat that,” he said on Good Morning America while promoting the film. “The insanity is nuts.”

7. Matthew McConaughey — Dallas Buyers Club (2014)

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Matthew is almost unrecognizable in Dallas Buyers Club, in which he plays a man who is diagnosed with HIV and given 30 days to live. “It was tough going, I’m not going to lie,” he said in 2014. “I was losing seven pounds every week. I’d have a Diet Coke, two egg whites in the morning, a piece of chicken, then another Diet Coke.” He continued: “I was always hungry, and irritable. My body resembled a baby bird with its mouth open, crying, ‘Feed me, feed me,’ and you realize momma bird ain’t going to feed you. It’s hard.”

8. Ryan Gosling — The Lovely Bones (2009)

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I know what you’re thinking, Ryan Gosling wasn’t even in The Lovely Bones? And you’d be correct! Which is what makes this story even more painful to hear. For context, Ryan was initially cast to play Jack Salmon (the grieving father ultimately portrayed by Mark Wahlberg), and believed that the character “should be 210 pounds.” In preparation, Ryan began drinking melted Häagen-Dazs ice cream whenever he was thirsty. When he eventually showed up to set 60 pounds heavier than his usual weight, he was fired by the film’s director, Peter Jackson. “We had a different idea of how the character should look,” Ryan said in 2010. “I just showed up on set, and I had gotten it wrong. Then I was fat and unemployed.”

9. Tom Holland — Cherry (2021)

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In a 2025 interview with Men’s Health, Tom’s experience making Cherry was cited as one of the biggest challenges of his career thus far. In the 2021 movie, Tom plays a soldier whose life spirals into crime and drug use. “I was trying to keep below 500 calories a day, I was working out like a crazy person, I was dropping weight really, really quickly,” he told the outlet, admitting that his crash dieting bordered on dangerous. “It’s not worth it, and it can actually promote quite considerable health concerns down the line.”

10. Jake Gyllenhaal — Nightcrawler (2014)

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Nightcrawler is such an underrated performance from Jake — especially when you hear what he went through while making it. In pre-production, Jake decided that he wanted his character, Lou Bloom, to look “gaunt,” so he took it upon himself to lose 30 pounds by eating “as few calories as possible” and running 15 miles each evening. “I knew if I was hungry that I was in the right spot,” he said in a 2014 Variety interview. There would often be evenings when he “wouldn’t eat at all,” and if he was hungry, he’d only eat “small pieces of meat, crackers or kale salad.” “Physically, it showed itself, but chemically and mentally, I think it was even a more fascinating journey. It became a struggle for me,” Jake recalled.

11. Natalie Portman — Black Swan (2010)

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While playing a top ballerina in Black Swan, Natalie said she was eating so little that “there were some nights that I thought I literally was going to die.” Eating so little, she lost over 20 pounds. Notably, some people from the ballet world thought Natalie’s character was too thin and criticized the movie for its unhealthy portrayal of ballerinas.

12. Mila Kunis — Black Swan (2010)

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Mila, who played Natalie’s rival ballerina in Black Swan, has echoed similarly troubling feelings about her restrictive diet while working on the movie. “I never watched what I ate [before]… And I’ll tell you this — I’m not promoting this at all — but I used to be a smoker, and so I smoked a lot of cigarettes and I ate a limited amount of calories,” Mila told Howard Stern in 2016. “1200 calories and I smoked.” Notably, Mila said she didn’t “starve” herself, but still found the experience “awful.” “I don’t recommend anybody ever doing it,” she said. “I don’t advocate this at all.”

13. Ashton Kutcher — Jobs (2013)

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Now, it’s time to finish off with what is perhaps the wildest inclusion on this list: Ashton landing himself in the hospital after trying to replicate Steve Jobs’ fruitarian diet. For context, the Apple co-founder — who died of pancreatic cancer in 2011 — was believed to be a fruitarian, which is a strict vegetarian diet that involves mostly eating fruit, along with some nuts, seeds, and grains. So, when Ashton played him in the 2013 movie, Jobs, his decision to replicate the diet led to a terrifying ordeal.

“First of all, the fruitarian diet can lead to, like, severe issues. I went to the hospital like two days before we started shooting the movie. I was doubled over in pain. My pancreas levels were completely out of whack,” he told USA Today in 2019, revealing he was diagnosed with pancreatitis. “It was really terrifying…considering everything.” Appearing on Hot Ones that same year, Ashton revealed that he’d tackled the diet by “drinking carrot juice nonstop all day long.”

Actors are wild. I have no idea how they do it. If you think of any more examples, let me know in the comments.The National Eating Disorders Association helpline is 1-800-931-2237; for 24/7 crisis support, text “NEDA” to 741741.The National Alliance on Mental Illness helpline is 1-800-950-6264 (NAMI) and provides information and referral services; GoodTherapy.org is an association of mental health professionals from more than 25 countries who support efforts to reduce harm in therapy.More on this