The story is worth reading in full, but for the sake of utility, here are Buettner's basic findings. These are not all pieces of scientific evidence. Buettner is up front that his article seeks to document the Ikaria lifestyle as it pertains to health, not to rigorously test for causation or even correlation between each individual component and longer life, although in some cases he presents compelling evidence for exactly that.
1) Plenty of rest: "Wake naturally, work in the garden, have a late lunch, take a nap."
2) An herbal diet: "Many of the teas they consume are traditional Greek remedies."
3) Very little sugar, white flour, or meat: "Low intake of saturated fats from meat and dairy was associated with lower risk of heart disease." A doctor cites "the absence of sugar and white flour."
4) Mediterranean diet: Olive oil, goat's milk, wild greens, wine, and coffee are all cited for health benefits. "Subjects consumed about six times as many beans a day as Americans."
5) No processed food: "Another health factor at work might be the unprocessed nature of the food they consume: as Trichopoulou observed, because islanders eat greens from their gardens and fields, they consume fewer pesticides and more nutrients."
6) Regular napping: Taking at least three a week was found to correlate with a 37 percent reduction in the risk of coronary heart disease.
7) Healthy sex lives after 65: "A preliminary study of Ikarian men between 65 and 100 that included the fact that 80 percent of them claimed to have sex regularly, and a quarter of that self-reported group said they were doing so with 'good duration' and 'achievement.'”
8) Stay busy and involved: "Social structure might turn out to be more important. In Sardinia, a cultural attitude that celebrated the elderly kept them engaged in the community and in extended-family homes until they were in their 100s. Studies have linked early retirement among some workers in industrialized economies to reduced life expectancy."
9) Yes, exercise: "It’s hard to get through the day in Ikaria without walking up 20 hills."
10) Little stress of any kind: Relaxed work and social cultures, little emphasis on time, and a caring community all get frequent mentions. For example, "You’re not likely to ever feel the existential pain of not belonging or even the simple stress of arriving late." Or, "Even if you’re antisocial, you’ll never be entirely alone."
11) "Mutually reinforcing" habits: "The big aha for me, having studied populations of the long-lived for nearly a decade, is how the factors that encourage longevity reinforce one another over the long term. For people to adopt a healthful lifestyle, I have become convinced, they need to live in an ecosystem, so to speak, that makes it possible. ... The power of such an environment lies in the mutually reinforcing relationships among lots of small nudges and default choices."