"I was called fat and ugly in the press almost my entire life ... it broke my heart and ruined my self-esteem," Osbourne, 26, says in the December issue of Shape, which hits newsstands Nov. 22 and sports her on the cover in a L*SPACE bikini. "It sets you up to hate yourself in a huge way."
At times Osbourne, who was a reality star early on in her family's MTV reality show The Osbournes, was so desperate to lose weight she considered undergoing surgery to solve the problem.
"I was always looking for a quick fix or a pill I could take," she says. "I even thought about getting the [gastric] band on my stomach. My mother had that surgery and I watched her lose a lot of weight. But we decided it would be better for me to try to slim down naturally."
As it turned out, getting back to basics was the answer. Osbourne, who has now lost 50 lbs., credits her former Dancing with the Stars partner, Louis van Amstel, in part, for teaching her how to get healthy through diet and exercise.
"He made me eat turkey burgers and salads and explained to me that a high-protein, low-carb diet would keep me energized," says Osbourne, who's now a size 2. "Then I started losing weight and realized, 'Oh, it's true what they say: Diet and exercise really work!' "
Staying MotivatedOsbourne says exercise remains a key component in keeping the weight off.
"My girlfriends and I just started doing plyometrics," she says. "It's a killer – it hurts so much. But when you walk out of there, you're like, 'I can't believe I just did that and my body looks this good.' "
But like many struggling dieters, Osbourne first had to overcome her aversion to exercise. "I hate to sweat," she says. "The trick for me was to ease into working out gradually. At first I spent 10 minutes on the treadmill – that's all I could do – when I worked my way up to 30 minutes. And I'm not lying when I tell you that at first I couldn't even do one sit-up, but now I'm up to 100."