PEOPLE:Levi Johnston's Playgirl prep: gym and moose meat

Johnston's latest gig is with Playgirl magazine.

How does Levi Johnston keep to the high-protein diet he needs to prepare for a Playgirl photo shoot?

With a rifle.

"Moose meat is very good for you, high in protein and very lean," his trainer, Marvin Jones, tells PEOPLE. "He's an avid hunter, so he has his own."

The 19-year-old father of former Alaska Gov. Sarah Palin's grandchild has adopted a 3,500-calorie low-carb diet as part of a grueling regimen to ready him for next month's photo shoot.

Full story at People Magazine