Matt Damon in Courage Under Fire (1996, 85%)
Damon dropped to 139 pounds at 25. From his Reddit AMA: “I had to run about 13 miles a day which wasn’t even the hard part. The hard part was the diet, all I ate was chicken breast. It’s not like I had a chef or anything, I just made it up and did what I thought I had to do. I just made it up and that was incredibly challenging.”