Matt Damon ‘went too far’ losing 50lbs in 100 days for movie role that had extreme health consequences

Matt Damon lost around 50 pounds in just 100 days for 1996 war thriller Courage Under Fire – a role which would have a tremendous impact on his health, as well as the trajectory of his career.

Set during the Persian Gulf War, Damon plays supporting character Specialist Andrew Ilario, an army medic who is suffering from a heroin addiction and survivor's guilt.

Despite only having a handful of scenes in the film, a young Damon was extremely dedicated to his craft, deciding to shed 50 pounds (over three-and-a-half stone or 22kg) in just over three-and-a-half months, creating the character's extremely malnourished appearance in the film.

In order to lose the weight so quickly, Damon adopted a strict diet and workout regimen, surviving off chicken, egg whites, steamed broccoli and baked potatoes while running 12 miles a day.

Matt Damon in Courage Under Fire (20th Century Fox)

The extreme diet led to 5ft 11in Damon dropping to around 135lb [61kg].

"I had to be thin and went on an unsupervised diet which could have killed me," he told The One Show during a 2022 appearance.

"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," he continued.

"I just made it up, and that was incredibly challenging."

A diet which doesn't take a nutritionist to figure out would be taxing on the body, with the strict routine inevitably having an impact on the 55-year-old's health.

Damon ended up needing medical supervision, being warned that his actions could have led to him permanently shrinking his heart.

The diet also meant the actor didn't 'have to act at all' as he was left feeling weak and unwell from his extreme diet.

"I was a wreck," he recalled. "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.

The dedication payed off, as Damon has gone on to have a successful career (Theo Wargo/Getty Images for Tribeca Festival)

"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."

While the performance had a negative impact on Damon's health, it did help boost his career in Hollywood. His performance caught the eye of Francis Ford Coppola, who went on to cast him in 1997's The Rainmaker. The film also caught the eye of Steven Spielberg, who later cast him in Saving Private Ryan.