The 21-year-old hasn't revealed how much weight she's lost, but did tell Shape how she did it: "I started slowly by walking the path around my house, and then eventually walking a little bit faster, and then actually going and climbing up the mountain [near my home]. So it was literally a mountain to climb, but I did that." She also began working with a personal trainer, taking Zumba classes with her mom, and making small changes to her diet. (05/19/11)
Celebrity Slim-Down Secrets
From Mariah Carey to Kirstie Alley, find out how some of your favorite stars shed some serious weight.