Diet Program: Weight Watchers
Hudson initially lost weight for her role in Winnie, but the singer-actress' impressive slim-down changed her approach to dieting. Opting to keep a food diary over self-deprivation, the Weight Watchers spokeswoman went from a size 16 to a size 4 and still commits to a workout of circuit training, weights and plyometrics. "I'm in the best shape of my life!" Hudson told PEOPLE.