After getting up to as much as 310 pounds during his final Super Bowl-winning season with the Ravens, he's now at 235 pounds and wants to become the cover model for a magazine backed by fitness company ViSalus, according to the Ravens' website.
Here's what Birk told the site about losing weight and changing his lifestyle:
"I wasn't going to go to Chipotle and get two burrito bowls at 9:30 at night anymore," Birk joked. "I never thought I would pose for a picture with my shirt off. But I wanted to show people that it can be done and that we're all in this together.
"I don't really think of myself as a model. Maybe a glove model."