I took a trip through asia recently and spent a day on Okinawa...when I asked about longevity, the first thing our guide said was not about diet, but that the people who live the longest there have a very moderate-stress lifestyle and work at a moderate but consistent pace their entire lives as part of their farming and fishing activity. They also have very strong and supportive social ties...
Also, the longevity of the average Okinawan has declined significantly, for which they blame sugar and "fast food" (which I equate to wheat, grain-fed meat and seed oils)