Robert de Niro

One of Hollywood’s most famous method actors, he commits to every role he takes – and in the past it could take a toll on the man’s body. Perhaps the most famous example of this was in Raging Bull, where De Niro not only got into boxing-fit shape to play Jake Lamotta – incidentally, the former world middleweight champion was his trainer – but also embarked on a binge-eating tour of Italy and France to play Lamotta in his overweight retirement. Rumour has it he gained between 66 to 97kg.