Abs-olutely! Summer's Sexiest Six-Packs

From Nick Jonas to Jennifer Aniston to Shakira, see which stars are impressing with their taut tummies

JENNIFER ANISTON

"When I really wanted to have a cheat day, I had to have a kale chip," Aniston said of the strict diet that helped her get into stripper shape for her nearly naked role in We're the Millers. "I was on a very like, you know, greens and vegetables and lean proteins and kale."