You get a role like this in a big action movie [like Jack Reacher] and you can go one of two ways: you can paint in broad strokes, which happens a lot in action films, or you can get very detailed.
When I did Casual, I just let myself put on weight because he's a schoolteacher. He's not meant to be muscle-y.
I change myself a lot. Some roles you don't want to be big, bulky, muscle-y guy and some roles you want to be a lean, marathon-runner physical type. And some roles you just don't want to be in shape.
I'm a trained actor and I can always tone it down, I can always simplify the work I've done. But if I'm asked to bring the nuanced and complicated work, I'll have it in my pocket, and all that information helps.
I had just come off of doing a play in Los Angeles which actually got me the role. It was called Bent and it was at the Mark Taper Forum. I was playing a homosexual in 1930 to 1934 Berlin who is eventually put into a concentration camp for the second half of the play. I had lost about 38 pounds for that.