From PEOPLE Magazine Click to enlarge
Lost 70 lbs.!

KIRSTIE ALLEY

The 5'8" Dancing with the Stars contestant, 60-who has declared the show "the best workout I've ever had!"-credits her trimmer waistline to daily five-hour ballroom rehearsals and her own weight-loss-supplement program, Organic Liaison, which she launched last year. Says the actress, "All of a sudden the weight is falling off me!"

Lost 30 lbs.!

JORDIN SPARKS

So long, size 12! "I've been hiking, using weights and doing Zumba [a dance fitness class]," says the 5'10" American Idol winner, 21, who recently posted a bikini photo on Twitter. And the singer doesn't make any excuses for herself: "It was just a shift in my thinking. Instead of talking about being more active, I find time to fit it in."

Lost 30 lbs.!

JONAH HILL

Last year the 5'8" comedian made his weight "a priority," he told Rolling Stone. "When I get stressed, I put on weight ... I never thought about what I ate, and I just didn't work out a lot." That was then: Hill-who next stars in the film version of 21 Jump Street-now works out regularly with the help of a trainer.

Lost 30 lbs.!

CARRIE FISHER

After ditching soda and spending an hour on the elliptical up to five times a week, "I've been able to fit into my old jeans!" says the 5'1" Jenny Craig spokeswoman. More important, Fisher, 54, is no longer hiding in her L.A. home: "I went to Lakers games a couple times. I would never have gone if I'd been the other weight."

  • Contributors:
  • CONTRIBUTORS Thailan Pham,
  • with Reagan Alexander,
  • Liza Hamm,
  • Jessica Herndon.