Look Great in '09

Celeb Weight-Loss Winners

See how Halle Berry, Jennifer Lopez and more hit the gym and shaped up for '09!

CHRISTINA AGUILERA

"I never felt my weight get out of hand," the singer said about carrying son Max Liron, born Jan. 12, 2008. So she waited until mid-March to exercise with trainer Tee Sorge. "I do the treadmill, I box, and I do a lot of weights. I feel so much better when I work out." She also burns calories breast-feeding – and by summer, Aguilera was back in body-hugging dresses.