LeAnn Rimes
Circuit training and yoga helped her slim down and tone up

Since she started practicing yoga four years ago, Rimes, 25, has whittled 10 lbs. off her 5'5" frame and dropped down to 14.4 percent body fat. "I was never really heavy at all," says Rimes, who now weighs 120 1/2 lbs. "Just softer." In addition to her frequent down dogs, Rimes spends an hour a day with a trainer at a Nashville gym, where her circuit training includes sprints, sit-ups and leg and shoulder presses. "I can bench press my body weight!" she happily brags. "I'm not just a skinny girl, I'm really strong." On the road, she keeps her tour bus stocked with healthy foods like cottage cheese, turkey, fruit and whole-grain breads. "I took my body for granted at 20," she admits. "Now I realize how amazing my body is and how important it is to keep in shape."

Carrie Underwood
An amped-up cardio routine helped the American Idol shed her baby fat

"I was a little bit heavier back then," says Carrie Underwood of her 2005 American Idol days. "I had a harder time finding clothes that I could feel good in." It didn't help that some viewers were candid in their online postings about the Season 4 winner's weight (at least one called the singer "chunky"). Underwood decided to slim down but didn't change her diet or fitness routine radically to do so. "I do work out, but not with a trainer," she told PEOPLE in September. "I just do lots of cardio." And yet, after a whirlwind year (which included two Grammy wins and a second CD, Carnival Ride), the singer, 24, looks leaner than ever. A longtime vegetarian, Underwood says, "I watch what I eat" but also admits to a weakness for cheese: "I can eat a pound of it. It's a real problem." (When she does overdo it, "My stylist gives me the 'I'm not feeling skinny today' clothing option.") A better idea? Keeping a snack tucked in her red carpet bags at all times. "I carry [whole grain] Kashi bars everywhere."

Craig Morgan
The former military man shed nearly 30 lbs. by adding old Army drills to his workout routine

Since hitting it big with his 2005 No. 1 hit "That's What I Love About Sunday," Craig Morgan admits he had become, well, big. "Last November someone handed me a picture of myself to sign," says Morgan, 42. "My face looked puffy and my shirt looked tight. I thought, 'I look huge!'" That motivated the 5'10" Morgan to swap sweets, fried food and pizza for lighter fare like sashimi. "I used to make fun of people who ate it," he says. "I'd tell them, 'That's bait.' But I love it now." The singer has also resumed the rigorous workout regimen he followed during a 20-year career in the Army, a routine that includes some 500 sit-ups, 200 push-ups and crunches and a two-mile run at least three days a week. The result: He dropped from 192 lbs. to 163 lbs. "I may never have six-pack abs," he says. "But I'm okay to take my shirt off at the pool now."

Kellie Pickler
A limit on junk food helped Pickler drop 17 lbs.

Here's the three-part weight loss philosophy of Kellie Pickler: 1. Don't count calories. "How depressing would that be if you always had to look at the back of a bag of potato chips? Just don't buy the family-size bag!" 2. Give up nothing. "I love steak, sushi, pasta! I eat everything." 3. Hit the gym but only when it fits your busy schedule. "This week I had Good Morning America, Regis and Kelly—I have not worked out at all!" Despite her diet defiance, the 5'1" American Idoler has lost 17 lbs. since May. How? Drinking more water and no longer eating when she isn't truly hungry, a bad habit that put 22 extra pounds on her during last year's American Idol tour. When she has time, Pickler, 21, swims, runs or fits in a game of football with her band. "It's not about losing weight at this point," explains Pickler, who is happy being 108 lbs. "It's about getting everything to stop flopping around!"

Jewel
Workouts with a trainer and 'hot-yoga' sessions helped the singer tone up

The downside to hitting it big at 20? "I still had baby fat," says Jewel, now 33. Despite "tremendous pressure to be thin," and more than one offering of diet pills, Jewel says she focused on "having a healthy body." Last winter, with a new gig hosting USA's Nashville Star, the 5'6" singer began working with a trainer at home in Stephenville, Texas. "My pants are looser," says Jewel, whose five weekly hour-long sessions combine weights, cardio and football exercises. "The time goes by quicker. It's better than if you just get on the elliptical and space out." Though she sticks to eating whole grains, lean proteins and an occasional piece of dark chocolate—"I read that it's good for you!"—Jewel admits that "it's hard to work out when I'm traveling." One solution: a hot-yoga studio in Nashville. "Whenever I'm in there, I'm like, 'Oh, good, I get to go do hot yoga!'"

Sugarland
The duo stay slim with yoga—and text messages

During the nine months Jennifer Nettles, 33, and Kristian Bush, 37, spent on tour in 2006, staying healthy proved a challenge. Postshows, "I'd be eating pizza to wind down," he says. Then, last summer, the Atlanta duo ("Stay") took up yoga—and before long, stretching replaced snacking on the bus, and the two began texting their daily meal plans to each other to keep on track. "A diet doesn't work if you're sneaking chocolate," Bush explains. Since their healthy makeover, Nettles (who also consulted a nutritionist) has lost 16 lbs. And Bush? "I have abs!" he says.

  • Contributors:
  • Ashley Williams/Nashville,
  • With Eileen Finan/Nashville.