Program Note: Tune in tonight to hear more on the Secrets to a Longer Life from Dan Buettner as he reports from the island of Ikaria. AC360° at 10 p.m. ET.

[cnn-photo-caption image=http://i2.cdn.turner.com/cnn/2009/images/04/22/art.bluezones.gianlucacolla.jpg caption="Buettner gets a ride on one of the All-Terrain-Vehicles popular in Ikaria given the steep terrain."]

Dan Buettner
AC360° Contributor

Seven years ago, I first had the idea to explore longevity by finding places where people lived the longest and study their lifestyle. So I called a man who lived down the street, near my home in Minneapolis.

A friend of mine had given me his name and I cold-called him. He picked up the phone enthusiastically and listened to my idea. He liked it and told me to fax over some information.

It was only after I sent my fax, explaining the details of what was to become the Blue Zones project, did I realize who I'd contacted. My neighbor, as it turned out, was Ansel Keys, an absolute titan in the world of diet research. His concern about diet as a public health issue began in the 1950s, decades before the word obesity entered the common vernacular.

As I prepared for my research, Keys encouraged me and essentially provided the entree to the world's best longevity scientists who helped me launch my project.

In the 1960s, he undertook the Seven Country Study, which first identified that saturated fats (like meat fat) are the villains in our diet. He also first identified the power of a diet rich in cereals, fruits, vegetables, beans, nuts, fish, wine, very little meat and olive oil-what he later coined the “Mediterranean Diet.”

People in Spain, Italy, France, Greece – all olive-producing countries - eat the diet and, not surprisingly, are among some of the longest-living people in the world. And Greece leads this pack of longevity superstars.

In the 1960s, 45 year-old Greek men had the greatest life expectancy in the world, four years longer than their counter parts in Japan and the United States–countries that were far more developed and offer better medical care according to scientists.

Here in Ikaria, people eat arguably the healthiest variation of the Mediterranean diet. And their diet was initially shaped by hardship.

Ikaria is a rocky, harsh island that rises sharply out of the sea. Angry ravines etch the slopes vertically in the rainy north, rocky step-like terraces corrugate the hills horizontally. People lived in remote villages away for the sea and the pirates it carried. They had to work hard to live off of this harsh terrain; the sea was a day's journey by foot. Therefore their diet favored the easy-to-grow and gather foods like figs, citrus, beans, vegetables, nuts and greens. Meat was a once-a-week treat and fish arrived only occasionally when a fish monger ventured up the steep hills into the villages.

As we've visited people aged 90 and over this week, we discovered over and over again that their diet is simple, seasonal and served fresh. And it the food is all cheap. Ikaria, like other Blue Zones in Sardinia, Costa Rica, and Okianawa, has very inexpensive foods and foods that have a very light impact on the environment. It makes me wonder: Could the recession be good for our health? (A pound of dried beans costs about a buck.) Perhaps “Blue” is the new “Green.”

Dan Buettner is the New York Times Bestselling author of Blue Zones: What the World’s Longest-lived People Can Teach You About Living Longer.

For more information on the Blue Zones Quest, go to: http://www.aarp.org/bluezones.

And are you curious about how long you’ll live? Check out Dan’s vitality compass, a quiz that will tell you what your biological age is, how old you’ll be when disease is likely to kick in and how long you’ll most likely be on this planet.