15 Eating Habits That Make You Live Longer

The Adventist Health Study 2, which has been following 96,000 Americans since 2002, discovered that people who ate a plant-based diet and included a small portion of fish up to once a day were the ones who lived the longest. In the Blue Zones overseas, fish is a common part of everyday meals. For the most part, the best fish choices are middle-of-the-food-chain species such as sardines, anchovies and cod, which aren't exposed to high levels of mercury or other chemicals.

Black beans in Nicoya, soybeans in Okinawa, lentils, garbanzo and white beans in the Mediterranean: Beans are the cornerstone of Blue Zones diets. On average, beans are made up of 21 percent protein, 77 percent complex carbohydrates and only a little fat. They're also an excellent source of fiber and are packed with more nutrients per gram than any other food on earth. The Blue Zones dietary average—at least 1/2 cup per day—provides most of the vitamins and minerals that you need.

Related: 9 Reasons You Should Eat More Beans

In three of the five Blue Zones, bread is a staple. But it's an altogether different food from the loaves most of us buy. Breads in Ikaria and Sardinia, for example, are made from a variety of 100 percent whole grains, including wheat, rye and barley—each of which offers a wide spectrum of nutrients and high levels of fiber. Other traditional Blue Zones breads are made with bacteria that "digest" the starches and glutens while helping the bread rise. This process creates an acid that lends the sour flavor to sourdough. The result is bread that actually lowers the glycemic load of meals. (It also has less gluten than "gluten-free" breads.) To find true sourdough, visit a bakery and ask about their starter. If they can't give you an answer, they're probably not making their sourdough in the traditional way.

Blue Zones dwellers consume about a fifth as much added sugar as we do. Centenarians typically put honey in their tea and enjoy dessert only at celebrations. The lesson to us: Try not to add more than 4 teaspoons of sugar a day to your drinks and foods. Have cookies, candy and bakery items only a few times a week. And avoid processed foods with sweeteners—especially when sugar is listed among the first five ingredients.

Related: 10 Easy Ways to Slash Sugar From your Diet

This appears to be the average amount that Blue Zones centenarians are eating. A recent 30-year Harvard study found that nut eaters have a 20% lower mortality rate than those who don't eat nuts. Other studies show that diets with nuts reduce LDL, or "bad," cholesterol levels by up to 20%.

Throughout the world's Blue Zones, people eat foods in their entirety: They don't throw away the egg yolk or juice the pulp out of their fruits. They also don't take supplements. They get everything they need from whole foods that are often grown locally. The takeaway? Avoid products with long lists of ingredients and shop at your farmers market when you can. Scientists are only beginning to understand how the elements in whole plants work together synergistically to bring forth ultimate health.

People in most Blue Zones have one to three glasses per day. Wine has been found to help the system absorb plant-based antioxidants. But it may also be that a little alcohol at the end of the day reduces stress, which is good for overall health.

Okinawans nurse green tea all day long, and green tea has been shown to lower the risk of heart disease and several cancers. Ikarians drink brews of rosemary, wild sage and dandelion—all herbs with anti-inflammatory properties.

People who live on the Nicoya Peninsula and the islands of Sardinia and Ikaria all down copious amounts of coffee. Research findings associate coffee drinking with lower rates of dementia and Parkinson's disease.

Worried about getting enough protein on a plant-based diet? The trick is to partner legumes, grains, nuts and veggies that supply all nine of the essential amino acids your body can't make on its own. Try these match-ups in the ratios described below.

1 1/3 parts chopped red peppers to 3 parts cooked cauliflower

1 part cooked chickpeas to 3 parts cooked mustard greens

1 part lima beans to 2 parts cooked carrots

1 1/2 parts cooked broccoli rabe to 1 1/3 parts cooked wild rice

1/2 part firm tofu to 1 1/4 parts cooked soba noodles