Recently came across this book. A very informative book on Okinawa diet by Marco Carestia, an Italian anthropologist specialized in Culture of Japan and Food Culture.
Okinawa is famous for having one of the healthiest population in the world with the longest lifespan. This world record is supported by scientific studies conducted over the years.
Centenarians express a high satisfaction level with their lives.
The ancient diet of Okinawa is low in salt, high in fruits and vegetables, and contain plenty of fiber and antioxidants.
The Okinawan lifestyle protect against the major diseases.
Elderly Okinawans often exercise both physically and mentally.

So if you want to know the secret for long life you must checkout this book.