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    Actors are committed to their craft. Many of them go to extremes to properly prepared for a role. Sometimes, they even put their health at risk with serious weight gain or loss. This is a list of actors who have taken that risk in order to accurately portray their character. 

    Mila Kunis in “Blood Ties” (2013)
    Although she dropped down to 95 pounds of muscle in the five months leading up to shooting “Black Swan” (2010), she now appears to have gone the opposite route, gaining it all back and then some for her upcoming role opposite Clive Owen.
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    Rob McElhenney in “It’s Always Sunny in Philadelphia” (2011)

    Packed on 52 pounds for the sake of comedy before shooting the seventh season of the series. He went from 160 to 212 pounds. He has since worked the excess weight back off.
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    Robert DeNiro in “Raging Bull” (1980)

    He first put on 20 pounds of muscle to play the young version of Jake LaMotto in the film, moving him from 145 to 165 pounds. Then, filming took a four-month hiatus in order for him to fatten up on Italian food and gain a record (at the time) 60 pounds to play the washed-up, older version of the same character. Scenes during his chunked-out period were shot as quickly and in as few takes as possible because director Martin Scorsese was worried about the actor's physical shape and heavy breathing. But the performance won him the Oscar that year, which was nothing to shake his sausage fingers at.
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    Christian Bale in “The Machinist” (2004)

    The gold standard in weight fluctuation, he shed more than 60 pounds for this role, dropping from a healthy 185 to around 120 (even though the director asked him to lose only 10 to 15).  He then bulked up to 220 for “Batman Begins” (2005), back down to 135 for “Rescue Dawn” (2006), up again for “The Dark Knight” (2008) and then down once more to 145 for “The Fighter” (2010). And, of course, he was recently seen again in Batman shape in “The Dark Knight Rises.”
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    Mark Wahlberg in “The Fighter” (2010)

    While obviously not as drastic as his co-star Christian Bale’s numerous weight gains and losses, Marky Mark worked to get in fighting shape for roughly four years for the role, only to have to let himself go and gain 30 pounds for the scenes in the film where his character retires from boxing. Then, after gaining this weight, he had to lose it within five months to shoot pick-up shots back in his original fighting shape.
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    Donnie Wahlberg in “The Sixth Sense” (1999)

    Lost 43 pounds for his brief role in the film.
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    Vincent D’Onofrio in “Full Metal Jacket” (1987)

    Gained 70 pounds (breaking Robert Deniro’s previous record of 60) in seven months for the film, shooting him up to 280.  He achieved this by eating lots of greasy food. In 2002, he would pull a similar feat by gaining 45 pounds for his role in the film “The Salton Sea.”
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    Jared Leto in “Chapter 27” (2007)

    Although the actor shed 25 pounds and befriended several real-life heroin junkies to play his role in “Requiem For a Dream” (2000), it was packing on 67 pounds to play John Lennon’s assassin Mark David Chapman that really did him in physically. He would choke down a large Domino’s pizza nightly in order to gain the weight. Reportedly, the mass amount of weight he packed on even confined him to a wheelchair on some days. He had to be prescribed Lipitor as well to handle the extra poundage.
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    Russell Crowe in “Body of Lies” (2008)

    Leaving his “Gladiator” (2000) physique behind, he put on 63 pounds of flab to play a fat CIA agent in the film.
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    Renee Zellweger in “Bridget Jones’s Diary” (2001)

    Packed on around 30 pounds for the film, and then did it again for the 2004 sequel, “Bridget Jones: The Edge of Reason.” If another sequel happens, she will go for the hat trick. You would think it would be easier to just write in that the character got her stomach stapled or something. But hey, that might be the edge of reason right there (clearly making fun of the stupid title).
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    50 Cent in “All Things Fall Apart” (2011)

    When you want to prove yourself as more than just a rapper and frequent gunshot victim, you drop down from 214 to 160 pounds in nine weeks to play a football player turned terminally ill cancer patient for a movie a lot of people didn’t see. He lost the weight by going on a liquid diet and walking for three hours a day. Sounds like good times all around.
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    Charlize Theron in “Monster” (2003)

    If you want to win an Oscar, just get fat or uglied up. Or in this case, both. The actress put on 30 pounds using the age-old Krispy Kreme and potato-chip diet. She also donned prosthetic teeth, makeup and buzzed off her eyebrows to make herself less attractive. Gross! Christina Ricci gained only 10 pounds to play the main character’s lesbian love interest in the film. No Oscar, though. Too bad. Should have gone fatter.
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    Tom Hardy in “Bronson” (2008)

    The actor, who used to be much, much skinnier, put on 42 pounds of solid muscle for the film by doing 2,500 press-ups a day for five weeks. He seems to keep getting bigger and bigger, keeping himself in full beefcake mode ever since.
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    Jennifer Hudson in “Winnie” (2011)

    While she, too, was in “Dreamgirls,” she was actually asked to gain 20 pounds for the film. It was no matter, though, as she dropped 56 pounds for her role as Winnie Mandela. And she’s kept it off since, as boasted in her numerous Weight Watchers commercials.
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    Vincent Cassel in “Mesrine: Public Enemy #1” (2008)

    Gained 44 pounds in four months for the role of Jacques Mesrine.
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    Benicio Del Toro in “Fear and Loathing in Las Vegas” (1998)

    Gained 40 pounds for the film by eating a lot of doughnuts.
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    George Clooney in “Syriana” (2005)

    Put on somewhere between 30 to 35 pounds in a month by gorging on a pasta-heavy diet. Did it pay off? Well, he won the Oscar for Best Supporting Actor that year, but the excess weight also caused him to tear his dura, which led to spinal cord leakage. Then again, he dates former WWE Diva Stacy Keibler and has millions of dollars to wipe his butt with every day if he so pleases. Sorry, the question has become irrelevant.
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    Tom Hanks in “Cast Away” (2000)

    Prior to filming, he allowed himself to get out of shape by not exercising so he could look like your average middle-aged person. Once the first half of the movie was shot, he took a year to lose 50 to 55 pounds and grow his hair out to shoot the second half of the film on the island. Prior to this role, he lost 26 pounds for his role as an AIDS patient in “Philadelphia” (1993), and before that gained 30 pounds by eating a lot of Dairy Queen for “A League of Their Own” (1992).
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    Adrian Brody in “The Pianist” (2002)

    Lost 31 pounds in six weeks, dropping him to 129, for his role as the Polish-Jewish musician. But if he could lose it, he could gain it, and that’s exactly what he did for “Predators” (2010). He added 25 pounds of muscle to play a mercenary in that film.
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    Toni Collette in “Muriel's Wedding” (1994)

    Put on 40 pounds in seven weeks for the film. That’s more like it.
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    Michael Fassbender in “Hunger” (2008)

    Lost over 30 pounds in 10 weeks to portray the leader of the 1981 IRA hunger strike in the film. Before this, he had gotten himself into Spartan shape by training heavily for 10 weeks for his role in “300” (2006).
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    Edward Norton in “American History X” (1998)

    Put on an insane 35 pounds of muscle in two and a half months for his role as the white supremacist in the film.
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    Mickey Rourke in “The Wrestler" (2008)

    Gained 27 pounds of muscle in seven and a half months through extensive weight training and eating six to seven meals a day.
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    Jonah Hill in “21 Jump Street” (2012)

    Though Hill said he lost 40 pounds just to be healthier, it is assumed the role in this film played a big part in the decision. Recently, he appears to have plumped back up yet again, though still not quite as big as he used to be.
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    Emile Hirsch in “Into the Wild” (2007)

    Dropped from 156 to 115 pounds for the role. That’s 41 pounds lighter for those of you who forgot your calculators.
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    Ewan McGregor in “Trainspotting” (1996)

    In order to lose the weight for this film, he was put on a no-alcohol and no-dairy diet. It took two months of this to get to the desired look of his heroin-addicted character. Cue the music:

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    Gary Oldman in “Sid and Nancy” (1986)

    He lost so much weight for this film that he had to be hospitalized. So method.
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    Will Smith in “Ali” (2001)

    Training for six hours a day, he gained 35 pounds in order to reach the real Muhammad Ali’s 220 pounds.
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    Sylvester Stallone in “Cop Land” (1997)

    Gained 40 pounds for the role of fat cop by mowing down pancakes as if IHOP was going out of business.