The only part of that page that discusses diet talks about how okinawa owes it's longevity to "A diet that is heavy on grains, fish, and vegetables and light on meat, eggs, and dairy products.'

If you look at the Wikipedia article for blue zones(areas with especially high levels of centenarians). https://en.m.wikipedia.org/wiki/Blue_Zone

They mention that one of the things that unites these areas is a mostly plant based diet.