Grab your nutcracker. Researchers who studied a Seventh-day Adventist community in Loma Linda, Calif., found that those who ate nuts five times a week had about half the risk of heart disease and lived two years longer than those who didn't. "Just eating a small portion—one or two ounces—does the trick," says Buettner. Stash snack packets in your office drawer or purse for mid-afternoon nibbling. Or add toasted walnuts or pecans to green salads, toss roasted cashews in chicken salad or top fish fillets with finely chopped nuts, suggests Buettner.

Be choosy about your circle. "Select your friendships carefully," says Buettner. "Gather people around you who will reinforce your lifestyle." Okinawans, some of the world's longest-living people, have a tradition of not just forming strong social networks (called moais) but also nurturing them. Kamada Nakazato, 102, never goes a day without meeting her four closest friends—from childhood—for a juicy gossip session. After you identify your inner circle, keep it from dwindling. Make an effort to hang on to good friends by keeping in frequent contact and spending time with them.