The Parks and Recreation actor, 33, has already gained 40 pounds since June in preparation for his role as a lawyer in the upcoming comedy Starbuck. The film centers around Vince Vaughn, 42, whose character learns he's fathered 533 children through sperm donations.
"This is what 275 looks like," Pratt tells Vulture while rubbing his belly. "All man right here."
Pratt says he hopes to weigh 300 pounds by November. To do so, he's been drinking "super gross but pretty tasty" weight gain shakes, in addition to eating at fast food restaurants. "I will hit a couple of burgers like it's laced with crack cocaine," he jokes. "Oooh, I love it."
One unfortunate side effect, Pratt admits, is that his energy is lower than ever. "If I just keep eating I can maintain a buzz, like a sugar food buzz. But if I'm in the background of a scene, I'm definitely sitting."
Pratt is no stranger to modifying his body for a role: He toned up to play a baseball player in 2011's Moneyball. "I just like to gain weight and lose weight," he tells Vulture. "It's a roller coaster. I just want to do this. I want to touch God."
This article originally appeared on Usmagazine.com: Chris Pratt Wants to Weigh 300 Pounds by November