Some people fall short of their diet and exercise goals until they finally find that one kernel that helps them achieve their targets – and for many, it's implementing the "buddy system," said a Baylor College of Medicine expert.

"It can be a very effective system to achieve a set goal, as seen in programs such as Weight Watchers and Alcoholics Anonymous," said Dr. Richard Pesikoff, clinical professor of psychiatry in the Menninger Department of Psychiatry and Behavioral Sciences at BCM.

Find reliable partner

Probably the most important factor in the buddy stem is finding a reliable partner – someone who has an attachment both to you and to the goal you have set.

"Look at it like a business contract – any contract is only as good as the person you've entered into it with," Pesikoff said.

You should look for a partner with the same goal as you and who has the ability to meet short-, mid- and long-term commitments, he said. You'll need someone who doesn't want to let you down, and vice versa.

Extra motivation

"You've set a certain goal because it's the right thing to do, but sometimes you need that added foot in the back," Pesikoff said. "A friend can provide that, and there's extra motivation because you don't want to let your friend down. It doesn't feel good when you leave someone out in the cold, waiting for you to show up at the gym."

Buddy systems can extend to more than one person, Pesikoff added. Running clubs are a great example of this. "If everyone else in your group is doing it, you'll be more likely to do it too," he said.

Goals can take a long time to achieve, usually because it takes a long time for cravings for such things like food to disappear. So be sure to find a buddy who will stick with you for an indefinite period and one that you can continue to turn to if cravings reappear.