How Mark Ruffalo Lost 20 Pounds For His 'I Know This Much Is True' Role

KEY POINTS

Mark Ruffalo's strict diet resulted in a 20-pound weight loss
To play another role in the HBO limited series, he had to gain weight
In "I Know This Much Is True," Ruffalo plays the Birdsey twins

Mark Ruffalo is willing to go to great lengths, just for a role, even if that meant only consuming 1,000 calories a day. As a result, he lost 20 pounds to portray the Birdsey twins in an HBO series.

The 52-year-old will play two characters on the limited series, “I Know This Much Is True,” which is based on the novel by Wally Lamb. Derek Cianfrance, the director of the highly awaited project, revealed that Ruffalo was on a strict diet where he shouldn’t exceed 1,000 calories daily and also did around “500 pushups a day.”

“I guess you could say he was always a little bit hangry. He was eating an egg white for breakfast and just starving,” the 46-year-old director told The Wrap.

Aside from a less-than-filling breakfast, Ruffalo also usually eats a small meal for lunch. The Oscar-nominated star would only consume a 120-calorie granola bar because of his diet, Us Weekly reported. All of these sacrifices eventually resulted in the very definition of “toxic masculinity,” the director added.

“It created this guy Dominic who was just wiry and aggressive,” the filmmaker added.

Before Ruffalo does a Dominic scene, the director ordered him to do pushups to achieve the character’s agitated personality. Cianfrance said the exercise was what made the “Hulk” star get into the zone.

All Dominic scenes were shot before the sequences of Thomas, the sibling who suffers from schizophrenia. To prepare himself for this role, he took some time off and gained around 15 kilos.

“We didn’t want it to be, like, I run and throw a wig on and do the same scene in the same day, so we took six weeks off to really separate these two guys,” Ruffalo said, adding that Thomas’ medications made him put on weight.

While losing the weight in an extreme manner was challenging, gaining the pounds back was also hard for the "Avengers" actor – something that Ruffalo had not expected.

“I thought I was going to have a fun time doing that, but when you’re force-feeding yourself, some of the romance of food sort of leaves,” the “Dark Waters” star said.