1. Hayden Panettiere
Less (clothing) is more. "There are parts of my body that I don't mind and parts that I can't stand," the actress admits. How she gets around it: bathing suits ("There's nothing constricting the bad areas") and "long, flowy summer dresses. You never feel fat."
2. Is a tomboy. "I've always played a lot of sports—volleyball, softball, baseball. I was a gymnast for nine years."
3. Walks with her dogs. When she's not working, Panettiere takes daily strolls with her pets up the hill near her West Hollywood condo.
4. Jennifer Aniston
Is consistent. While filming Marley & Me
in Miami, the actress has been working out for an hour a day on the hotel's elliptical machine.
5. Makes workouts fun. Aniston does her cardio to her iPod.
6. Watches the cocktails. She's fond of red wine and lychee martinis— but usually sticks to just one.
7. Eats fish. In Miami, a typical meal for Aniston has been three rolls of sushi or a fish entrée at Michael's Genuine.
8. Hugh Jackman
His workouts consist of "interval strength training"—doing, say, a squat and a shoulder press at the same time.
9. ZAC EFRON
"I definitely love to stay active. If it gets me outside and gets me moving, then I love doing it."
"I go through a phase where I just eat whatever. Then when I'm finally fed up, I stop and I'm back on my regimen. And it keeps going like that."
11. "I do the elliptical for 30-40 minutes. I speed it up in between, then I come down, then I come up some more."
12. "I hate vegetables but vegetables help. Carbs are my biggest enemy."
13. "If I know I'm going on vacation, I'll do Pilates for two weeks straight."
14. Flaunts her assets. Her favorite body part? "My butt. It makes my clothes look good. It's not a dress—it's a dress! My butt perks up everything."
A MODERATE APPROACH
Yes, these stars say: You can eat pizza and skip the gym.
15. Anne Hathaway
"When I'm working, I'm incredibly disciplined, because when you're portraying someone else, your body isn't your own. But when I'm not working, I think less about what I eat. For example, last night I had a club sandwich and two nights ago I had pizza. You've got to live!"
16. "I normally eat everything under the sun. But once a year for a month, I eat fruits, vegetables, nuts and lean fish, and I feel great."
17. "Just have a little bit of something that you want. Don't overdo it."
18. The star's trainer Joe Dowdell says three days of cardio a week "is healthy. You shouldn't go to extremes."
19 Penélope Cruz
Doesn't obsess about working out. "She gets in, gets the work done, gets out," says her trainer Gunnar Peterson.
20. Gets plenty of sleep. "I think she gets more than eight hours a night," Peterson says. "She never comes into a workout sluggish or tired."
21. Doesn't believe in bad eating days. "If she eats fries, then she eats them and moves on to the next thing. It's not a big deal," Peterson says.
22. Keeps her body proportioned. "She has a butt—and the key for anyone with a butt is to do adequate shoulder work, to balance things out."
23. Gwyneth Paltrow
Works out six days a week, doing dance aerobics for cardio.
24. Sets goals. For the upcoming Iron Man
, "she wanted a Victoria's Secret butt, like Gisele!" says her trainer Tracy Anderson.
25. Recently completed a five-day "live food" (raw and organic) fast from N.Y.C.'s Organic Avenue.
26. Katherine Heigl
Follows Harley Pasternak's 5-Factor Diet, eating five small meals a day.
27. For exercise, works out with kettle balls twice a week.
28. Beyoncé Knowles
"She loves southern cooking," says her rep, but when it's time to trim down, "she packs up on the salads, grilled fish and chicken."
29. David Beckham
"He is much more health conscious since moving to Los Angeles last year," says a family friend. "He is training twice a day now."
30. Kate Hudson
Favors salads for dinner and yogurt with honey for breakfast.
31. MARIO LOPEZ
"Break a sweat every day. I don't feel like I've woken up if I don't break a sweat first."
32. Eats every three hours.
33. Has a cheat day once a week. "I eat a steady flow of tacos, ice cream and cookies."
34. Curbs cravings with peanut butter. "It has some fat, and it's tasty."
35."I like to keep my muscles guessing. I like to run, bike, dance when I can. A little yoga. And I swim when it's nice out."
36 Mariah Carey
Water aerobics "is actually three times more effective" than other workouts, she has said.
37. "I have my trainer move in with me—so I can't sneak food!" she says.
38. Sticks to what she has called a "bleak" diet of lots of soup and fish.
39. America Ferrera
Restricts pasta to lunchtime, says her nutritionist Philip Goglia.
40. Doesn't have any starches (like potatoes or bread) at dinner.
41. Has a mid-morning snack (usually fruit) to keep up her energy.
42. SUSIE CASTILLO
Picks fitness classes over "boring" cardio machines.
43. Doesn't mix meats and starches because "it's too hard for the body to digest."
44. Fills up every a.m. with a glass of juice made from romaine lettuce.
45. Eats 70% dark chocolate only.
46. "Have a colorful plate. I make a spinach salad with things like blueberries, apples and carrots."
47. "As I've gotten older, I definitely have to watch more of what I'm eating and work out a bit more, run a bit faster."
48. "To get great legs, you have to do lunges, squats and steps," says trainer Teddy Bass, who does all that with Diaz.
49. "I eat a lot of green and raw vegetables, and I juice a lot. And I do the trampoline with my kids!"
50. "I'm into horse show jumping. It's an awesome butt, thighs, inner legs workout. You can't walk for days if you haven't ridden in a while!"
51. "Chocolate is not cheating! After a salty meal, you need a little bit of sweet. This is living, not cheating."
52. "When I'm in focus mode, I do training six times a week. Carbs only in the morning. And I try not to eat at least two hours before bed."
53. "You have to find a workout you love. I hate the gym, but I just took up pilates and it has changed my life."
54. "Running is the only thing that gets me out of my head. It's meditative and it makes you pretty in shape."
55. "Having a child means having lots of sweets in the house. I try to keep that stuff in the cupboard and out of sight."
ALANA DE LA GARZA
56. "Every couple of months I check myself in the mirror. If I go, 'Your jeans look a little tight,' it's time to cut out the nachos."
57. "I don't diet. There's going to be barbecue and macaroni and cheese—but I'll have broccoli and salad the next day."
58. "I love restaurant pasta—the sauces. So now I ask for the sauce to take home and put it on whole wheat or rice pasta."
59. "I can't do diets. I find when I'm on them, I immediately feel like breaking them and eating a lot."
60. "On occasion a bowl of Life cereal for dinner is the greatest thing. And I'm obsessed with Pink Lady apples."
61. "I go with my trainer on a 35- to 40-minute walk. I'm speaking out for all those people who hate to run. I hate it too!"
62. "Sleep is like the holy grail. My trainer says if you're tired, your workout will suffer. Sleep is the magic stuff."
63. "I can do a good workout in less than an hour: 30 minutes on the treadmill, 10 minutes on the bike, then 10 minutes of crunches."
64. "I've been really into boxing. You don't remember how hard jumping rope is! It really works my arms and I like the aggression of it."
65. "I don't feel guilty. I love hot dogs, which are so unhealthy; but I have them on occasion so I don't feel deprived."
66. "I don't cut anything out. If I want potato chips, I have three or four. After that, the craving is pretty much gone."
67. "If there's a dessert table and I like it all, I take a little piece of everything, take a bite and throw the rest away."
68. "I just became a vegetarian [recently] and I've gotten a lot thinner. And if I take out the wine, I tend to slim down quickly."
69. "I drink a lot of water. I love the little Crystal Light packets that make you feel like you're drinking more water."
70. "I hate that feeling of being so full that you feel like you're gonna burst, so I try not to do that."
71. "I like my shape, but to get rid of cellulite I focus on toning, doing martial arts on a treadmill. And Spanx are my best friend!"
72. "I do Fresh Dining, which is delivered to your home. And the DVD P90X—it's a 90-day program that transforms you."
73. "I work my butt off. Really. I run at least 45 minutes every day. And then three days a week I do weights."
74. "The quickest calories that add up are the cocktail calories. Might as well have a cheeseburger if you have a great margarita!"
75. "To help my muscles rebuild after I work out, I have a small serving of cottage cheese."
76 Kate Walsh
Rotates Pilates with weights and circuit training.
77. "I avoid sugar, serious sugar, because you go up then come down and crash."
78. Practices portion control so she doesn't have to be "terrified of carbs. I want to be able to have a glass of wine."
Has meals delivered from Diet Designs.
80. "I do organic vinegar shots. Two tablespoons after lunch and dinner. It helps take toxins out of your body."
81. Makes "fattening food low-fat," like lasagna with turkey meat and cottage cheese.
82. Jessica Biel
"She's game for anything, like 10 reps of standing on one foot doing a single leg squat," says trainer Valerie Waters.
83. When not with her trainer, does yoga and running on her own.
84. MARY J. BLIGE
"I'm not a morning person, but I get up and knock out exercise, because if I don't, in the afternoon I'll be tired and there's tons going on."
85. When it comes to alcohol, "once I get my buzz, I shut it off. Two drinks is my limit."
86. Blige's trainer Gregg Miele (left) reinforces this mantra: What you eat in private shows in public.
87. Vanessa Williams
"I drink a beet-carrot juice in the morning or an apple-strawberry-pear juice."
88. "On vacation I enjoy the desserts—and work extra hard when I come home."
89. Ashton Kutcher
When it comes to feeling sexy, Demi's husband once told PEOPLE that he relies on "quiet confidence."
90. Catherine Zeta-Jones
"I do a lot of swimming because I live in Bermuda, both in the ocean and in the pool. I've got to drag myself to the gym, but when I finish it, I enjoy it."
91. Her most common meal? Lightly grilled chicken with a little oil and lemon and a feta cheese salad.
92. Cuts down on bread when she needs to slim down.
93. Ryan Phillippe
Goes for daily runs at the UCLA tracks.
94. Sticks to an all-protein diet, ordering steaks from L.A.'s Dan Tana's weekly.
LOOK 10 LBS. THINNER—INSTANTLY!
95. "Just put your shoulders back and smile."
96. "Don't wear white, wear black. Very. Fitted. Black!"
97. "You know what's totally amazing? Spanx!"
98. "Black, high-waisted, really tight skirts. That's it!"
99. "If you wear a dress with a belt placed high, you accentuate your waist."
100. "I love baby-doll dresses, so people look at my legs—not my stomach!"
- Reported by Amy Elisa Keith/Los Angeles,
- Monica Rizzo/Los Angeles,
- Tiffany McGee/New York City,
- Alyssa Shelasky/New York City,
- Michelle Tan/New York City,
- Charlotte Triggs/New York City.