5. Don Cheadle
For most of Cheadle’s successful career, he played waifish characters. Then, he landed the role of Lieutenant Colonel James Rhodes in the Iron Man movies. Rhodes is Iron Man’s doppelgänger, a mash-up of Captain America and Iron Man. For that role, Cheadle had to gain some mass, especially since he replaced the original actor for the role, Terrance Howard. How much Cheadle gained, the actor is not saying, but he did put on some mass.