Plyometrics: Secret to Kelly Osbourne's Sexy New Body?

(CBS) After years of being called fat and ugly, Kelly Osbourne has dieted and exercised her way to a killer new body - and she's not about to keep it under wraps.

The 26-year-old star of the MTV reality show "The Osbornes" graces the December cover of Shape magazine in a sexy red bikini. "How she lost 50 pounds (and keeps it off), reads the accompanying coverline.

Osborne told Shape the taunts fueled the drug problem that required three trips to rehab to overcome - and led her to seek solace in food after she gave up drugs.

"I replaced the drugs with food and just got fatter and fatter," she told the magazine. "I'm an emotional eater. When I get upset, my diet goes out the window."

She desperately wanted to lose weight but didn't know how, telling the magazine she considered diet pills and even surgery. "I was always looking for a quick fix or a pill I could take," she said.

Ultimately, Osbourne's former dance partner on "Dancing with the Stars," Louis van Amstel, showed her how to lose weight the old-fashioned way.

"He made me eat turkey burgers and salads and explained to me that a high-protein, low-carb diet would keep me energized," Osbourne said. "Then I started losing weight and realized, 'Oh, it's true what they say: Diet and exercise really work!'"

But Osboure didn't use just any old exercise. She got heavily into plyometrics, an exercise technique that involves high-intensity jumping and other movements that require the muscles to move very fast and forcefully.

"It's a killer - it hurts so much," Osbourne said. "But when you walk out of there, you're like, 'I can't believe I just did that and my body looks this good.'"

No argument there.