Anyone see Chris Pratt's (from Parks and Rec) changes?

FittingIn

I've seen the chubby, clueless character on Parts and Recreation. However, in six months, he totally changed into a very fit guy for a movie role. Unfortunately, he then added 60 pounds for his next role.

Anyway, does anyone know what approach he took to become so fit? The only clue I've heard is that he gave up beer.

http://img.gawkerassets.com/img/18t8g4ublpcbgjpg/k-bigpic.jpg