1. Christian Bale and his extreme thinness in 'The Machinist'
One of the most surprising performances in cinema. Christian Bale played Trevor Reznik, a man who suffered from insomnia.
He began to lose kilos four months before filming until he reached 50 kilos (he lost 28 in total). He himself wanted to go down to 45, but the producers forbade it because he could have health problems (and of course, judging by the film, he didn't need it at all). Furthermore, as soon as filming finished, he had to regain his weight and 30 kilos more; He was beginning to prepare his role for Batman Begins.
2. Tom Hardy played the real criminal Bronson
Tom Hardy played the role of criminal and kidnapper Charles Bronson, who is currently in Woodhill Prison (United Kingdom). The actor had several telephone conversations with him and they even met several times in prison. Bronson himself admitted that he was impressed by how Hardy had changed his physique for the role and how well he imitated him.
3. Jake Gyllengaal as a boxer in 'Southpaw'
Gyllengaal trained six hours a day for six months to gain seven kilos of muscle. According to Antoine Fuqua, the film's director, "we literally turned him into a beast."
4. Chris Pratt in 'Guardians of the Galaxy'
He weighed no more and no less than 136 kilos when he auditioned for the Marvel movie. In his own words, he lost 60 kilos in six months thanks to "three or four hours a day of hard, consistent work."
5. Natalie Portman in 'Black Swan'
"There were nights when I literally thought I was going to die," said the young actress. She lost nine kilos and her diet was based on a little carrots and almonds. In addition to the physical stress that her body had to endure with such a strict diet, she had to practice dancing for eight hours a day. Portman acknowledged that after this role she realized how much a performance affected real life.
6. Chris Hemsworth, an example of consistency in 'Thor'
He trained with Duffy Gaver, a Navy SEAL, until he gained twenty pounds (and all in muscle!). According to his coach, people believed he was doping, but he was following a diet based on a lot of red meat and protein shakes. "I just wanted to be like Thor."
7. Matthew McConaughey and his role as a drug addict
He lost almost 20 kilos and won the Oscar for best actor in 'Dallas Buyers Club'. Despite how dangerous those conditions were for his health, he acknowledges that he had a lot of mental energy throughout filming.
8. Charlize Theron and her transformation into 'Monster'
One of the most striking examples of interpretation. Despite having gained eleven kilos based on donuts and French fries, the actress admitted that she did not consider herself to be fat. What was most difficult for her was leading the careless lifestyle that characterized her character in order to get into the role.
