Traditional Okinawan diet

The research behind the famous story comes mainly from the Okinawa Centenarian Study and from Bradley and Craig Willcox with Makoto Suzuki. Their 2007 paper in the Annals of the New York Academy of Sciences studied six decades of archived data on Okinawans aged 65 and over, and found low calorie intake and a negative energy balance in younger years, little weight gain with age and low death rates from age-related disease. They read it as support for the idea that mild calorie restriction helps people age well. A 2014 review by the same group says the diet was anchored by sweet potatoes, green and yellow vegetables, soy foods and medicinal plants, with marine foods and lean meat in moderation, and that sweet potatoes once supplied over half of daily calories.

Okinawans have their own words for the idea. Nuchigusui means 'medicine for life' and kusuimun means food as medicine, and the OCVB still frames island cooking that way. Foods that recur in this writing include goya, soy foods such as shima-dofu, mozuku, turmeric, and pork simmered long enough to separate the meat from the fat. A Naha kitchen such as Tsuchi Kaoru builds its menu on the kusuimun saying.

The picture has changed. Sweet potato gave way to white rice, bread and noodles after the war, and the 2014 review notes that within two generations Okinawans went from the lowest BMI in Japan to the highest. Gavrilova and Gavrilov argued in Gerontology in 2012 that the longevity advantage shows only in generations born before the war and that diet westernisation explains the loss. In the Ministry of Health's 2020 life tables, life expectancy at birth was 80.73 years for Okinawan men, 43rd of 47 prefectures, and 87.88 years for women, 16th. Older Okinawans still do well, and Okinawan women aged 65 and 75 had the longest remaining life expectancy of any prefecture in 2020.

Treat the bigger claims with care. Okinawa appears as a 'Blue Zone' in tourism writing, and the researcher Saul Newman argued in a 2024 preprint that blue zones line up with low incomes and short average lifespans, and that errors and fraud inflate remarkable age records. Japanese and English sources agree that no single food has been shown to slow ageing. Willcox and colleagues compare the old Okinawan pattern with the Mediterranean and DASH diets, which share its heavy use of plants and its low saturated fat.