Before there was Christian Bale, Robert De Niro was the king of transformational method acting — and no film establishes this better than the Martin Scorsese classic Raging Bull. In the film, DeNiro plays Italian-American middleweight boxer Jake LaMotta, whose self-destructive behavior is chronicled over the course of several decades, and De Niro takes it upon himself to show those decades of wear through his real, physical appearance.
At the time of the film’s release, De Niro’s 60 pound weight gain was the most by any actor for a film role, but what makes the actor’s physical change so remarkable is the extremes he went through during the course of one shoot. For the majority of the film, De Niro was required to maintain the body-type of a boxing contender and only in the last scenes in the film, which depict an older, overweight LaMotta, does De Niro swing wildly in the opposite direction.
And as if the weight gain alone wasn’t enough, De Niro added the weight in truly epic fashion: the production was shut down for several weeks while the actor went to Italy and ate as much pasta as he possibly could. By the time he got back, Scorsese was so alarmed by De Niro’s weight gain and labored breathing that production was again shut down as the director feared for the actor’s health.
The shooting of the movie and De Niro's dedication to the role earned him serious respect in the film industry, on top of his amazing acting skills, and set the bar for all actors doing transformative roles since.
(Source: PK Baseline)