Everyone has their own weight-loss secrets, including several American Idol finalists who recently dished how they stay fit to Us Weekly.

"Touring gave me the kick-start to eat healthy and start exercising," season five winner Taylor Hicks told Us after the 30-year-old shed nearly 20 pounds since his victory in May.

In addition, Hicks said he rid french fries and other fatty foods from his diet in an effort to eat healthier, a move that was also used by 23-year-old another champ, Carrie Underwood, who is a vegetarian.

"I find that the more health food I have, the more health food I eat."

American Idol season two winner Ruben Studdard, who has a history of diabetes in his family, is also trying to lower his weight and increase his health by becoming a vegetarian. "It's been working," Studdard told Us.

Some eschew the whole idea of dieting, such as original Idol winner Kelly Clarkson, who travels on tour with a personal chef.

"It's all about portion control," the two-time Grammy winner told Us. "If you deprive yourself, you'll just go nuts and eat way too much."

Meanwhile, Katharine McPhee said she simply stops eating when she's full.

"I eat what I want - pizza, pasta with marinara sauce, ice cream, bread - but now I pay attention to how I feel while I'm eating."

Aside from what's on their plate, the American Idol stars also said exercising was key in slimming down and staying fit. Both Underwood and McPhee said they have trouble finding time to exercise, but still make sure it's a regular part of their schedule. Underwood said she's her own trainer, utilizing personal exercise machines and workout DVDs.

"If I can get myself to get up, I'll go on the cross-training machine or do an outdoor activity like swimming," Underwood said. "Any activity is better than nothing!"

A high-school track athlete, Clarkson said she tries to chose fun workouts like playing tennis and boogie-boarding, but still puts in 90-minute treadmill runs daily. "You have to have endurance and be at your utmost health," Clarkson told Us. "I enjoy working out."

Perhaps the most gains made by a former American Idol contestant in an effort to lose weight was by Idol season three finalist Jennifer Hudson, who lost 60 pounds and shed 12 dress sizes since her 2004 appearance on the show. Eliminating fried foods from her diet, jogging regularly and receiving some encouragement from her mom were all things that Hudson said contributed to her new figure.

"It's all about healthy living," Hudson told Us.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.