Take five minutes while you’re drinking your coffee or packing your lunch to phone a friend and share your exercise or health commitments for the day, recommends JJ Virgin, celebrity nutrition and fitness expert and the bestselling author of Six Weeks to Sleeveless and Sexy. Setting your intention will make you more likely to follow through.

Schedule a weekly weigh-in with your friends, says Virgin. Knowing you’ll have to report your number will keep you accountable during the week.

“Do a cleanse together,” say Sara Haley, Global Reebok Master Trainer, independent fitness consultant and creator of the upcoming prenatal fitness DVD Daily Sweat Pregnancy Program: Expecting More. “I love the Isagenix Cleanse because you can eat on it!”

Do you have a BFF who’s good at doling out tough love? Ask her to be your lifeline, says Virgin. That way, when a craving strikes you can call or text her before you binge and she can remind you of the goals you’ve set and the commitment you’ve made to living healthier. 

Have you always wanted to try Bikram yoga but didn't want to buy an expensive package? “Deal-of-the-day websites such as Groupon and LivingSocial offer deep discounts on monthly packages and are great ways to take advantage of a new type of workout,” says Heather Bauer, RD, CDN, founder of Nu-Train and author of Bread is the Devil (out January 2012). “Buy two coupons and surprise a friend for her birthday or upcoming holiday.

Encourage each other with small, health-boosting gifts. “We love giving discounts when you buy for your buddy at HappyBellyBags.com,” says Koff. But you don’t even have to spend money. Forwarding e-mail coupons or Facebook freebies from wellness companies, such as Gaiam or Kashi, is also a great way to inspire better buys.

Motivated by money? “Agree to pay one of your friends if you don't achieve 3.5 hours of activity per week,” suggests Aschan. “It will help you to implement your activity plan and stay motivated.” Want to raise the stakes? Wage at least $100 on LoseItorLoseIt.com. The website is run by two computer programmers who will keep your money—not even donate it to charity!—if you don’t achieve your weight loss goal.

See what happened when one of our writers bet $500 that she’d lose 20 pounds in 10 weeks.

“Bring your friends to try out a new workout such as boot camp or pole dancing at your local gym,” says Aschan. Variety helps prevent boredom and can make you more likely to work out at a higher intensity, enhancing your results.

Sign up for a group fitness class or get together at a friend’s house to do a fitness DVD, says Haley.

Check out these calorie-torching exercise DVDs.

Make your health a priority by planning a girlfriend’s wellness weekend, suggests Leslie Bonci, MPH, RD, CSSD, LDN, director of sports nutrition at the University of Pittsburgh Medical Center and author of The Active Calorie Diet. Spend the weekend (at home or away) cooking nutritious food, exercising and indulging in spa treatments.

“My wife, who is a private chef, invites her friends over once a month and teaches them to cook simple, delicious, healthy meals,” says Cardiello. "Anywhere from three to six women gather in our kitchen to share their desire to learn and support and encourage each other in all aspects of life. If you don't have the luxury of having a friend who is a chef, then organize a monthly gathering where you and your friends can share healthy recipes and other weight loss tips and tricks.”

“With a friend, pick a new activity—like spinning or indoor rock climbing—sign up for classes and go together to buy all of the necessary equipment,” says Steve Ettinger, fitness expert and author of Wallie Exercises. ”By making each other spend money, you’re making a commitment to follow through with the activity. Plus, you’ll feel more accountable because if you back out your friend will be directly affected as well.”

“Take a night out each week to go for a stroll or brisk walk with a friend,” says Cardiello. “Walking with another person is not only safer, but it also holds you accountable.” If none of your friends are walkers, make a new one by posting a sign on the bulletin board at your gym or join a local group through MeetUp.com.

It’s easy to get excited to exercise when you have cool new clothes to wear. Go shopping with a friend for fun workout duds that will make you look as good as you’re going to feel, says Mitzi Dulan, RD, CSSD, nutritionist and owner of Mitzi Dulan’s Adventure Boot Camp.

Want to feel like you’re 15 again? Organize a fun-filled afternoon of sports like volleyball, basketball or even just Frisbee with a friend and your kids, says Cardiello. It will bring out the athlete in you and force you to try to keep up with the endless energy of the younger set.

“Competition can be healthy,” says Bauer “Make small weight loss goals with your friends and see who meets them first. Each goal that is met should have a small reward—for example, coffee gift cards or gift certificates for a manicure. Keep it friendly and you'll stay motivated.” Keep track of everything online or race out-of-town friends using websites such as WeightLossAndWin.com, Slim2Win.net and BuddySlim.com.

There’s no denying that healthy food can be pricey. To beat obesity on a budget, start an informal co-op of sorts, suggests Bonci. Do a weekly group cook of healthy foods and then split up servings, or buy herbs in bulk and then share the cost.