The 36-year-old, who lost almost 50 pounds in 100 days for his role as a heroin-addicted soldier, insisted that although the weight loss helped him fit in the character, it was 'just too much'.
"I went too far. I got sick and I wouldn't do that again because it was just too much. At the same time it helped the performance," Contactmusic quoted Damon, as saying.
The actor who followed a self-prescribed diet and fitness regimen to shred weight for only two days of filming, revealed that he felt like a 'wreck' but did not tell anyone about his condition.
"I didn't have to act at all - I was a wreck. I was getting dizzy spells and hot flashes. I didn't say anything to anyone for a while because I was afraid I might be really ill," he said.
After the filming, Damon was told by doctors that he was fortunate his heart did not shrink. The actor was on medication for several years to correct the stress inflicted on his adrenal gland, but he maintained it was worthwhile to properly reflect his character's anguish and to show the industry how committed he was to the role.