The Okinawa Shock: As life expectancy falls, world watches with bated breath

It's lunchtime in Naha, Okinawa, and a city center restaurant hangs out a signboard advertising its "A Lunch," a set meal featuring tonkatsu (fried pork cutlets), fried fish, ham and eggs.

Add rice and miso soup to the equation and it seems this meal alone could cover a Japanese person's average daily calorie intake (1,859 kilocalories). The A Lunch is said to date back to before Okinawa was returned to Japan, to a set meal made for taxi drivers who drove foreign clients, a glamorous job at the time. A nearby stall, meanwhile, does a brisk trade in "Spam onigiri" (rice balls with luncheon meat).

Okinawans used to have a simple diet that included plenty of potatoes and vegetables, but this changed dramatically during the period of the U.S. occupation that lasted from the end of World War II until 1972.

What impact will these kinds of dramatic dietary changes have on body shape and life expectancy? This question has drawn the eyes of the medical world to Okinawa.

Hideaki Tanaka, a doctor who treats lifestyle-related diseases in Tomigusuku city, was interviewed on the topic by a French TV channel last autumn. "We want to tell people about the crisis in Okinawa," crews from France said to him. He has also been interviewed by the U.S.'s CNN channel and South Korea's KBS. As Tanaka sees it, Okinawa, with its drastic dietary changes, is attracting attention as a "testing ground" for the world.

"The Okinawan crisis is a sign of things to come for the rest of the planet. Perhaps people are coming here to try to find solutions to the problem," he suggests.

In a Japanese public health and nutrition survey into obesity levels, released for the first time this year, Okinawa topped the national rankings, with 45.2 percent of all adult males aged 20 to 69 classed as obese with a BMI of 25 or over.

According to a study by Hidemi Todoriki, an associate professor at the University of the Ryukyus Graduate School, the fat content of the Okinawan diet has risen sharply over the years, up from 10 percent in the 1960s to more than 25 percent in the 1970s. It now stands at the 30 percent mark, up there with Western diets. At the same time, consumption of konbu seaweed, a traditional ingredient in Okinawan cooking, has fallen to less than a third of what it was 30 years ago.

The BMI of a 40-year-old Okinawan male was below the national average in 1949, soon after the war. However, with social factors also taking their toll, things had changed by the time the territory was returned to Japan. By 1982, the BMI of this demographic had risen to around 25, higher than the national average of 22.8.

The change of diet has also put to the test Okinawa's longstanding claim to be "the long-life prefecture." After ranking fourth in 1995, the average life expectancy of Okinawan males plunged to 26th in the national chart in just five short years, prompting talk of a "26 shock" within the prefecture. Nothing much has changed since, with the most-recent survey in 2005 placing Okinawa 25th in the national rankings.

The situation has also deteriorated when it comes to lifestyle-related diseases, with younger people aged 65 and under accounting for more than 20 percent of all deaths in the prefecture, the highest level in Japan. To explain this phenomenon, some have pointed to the lack of exercise in this car-driven society, while others have touched on economic problems, such as the reluctance to spend money to meet ballooning medical costs.

At the same time, though, people are starting to reappraise the food eaten by ordinary people during the era of long life expectancy. For example, the prefecture is examining the idea of bolstering school meals with Okinawan vegetables, which can help ameliorate high blood pressure and reduce body weight.

Hiroaki Masuzaki, a professor at the University of the Ryukyus Graduate School of Medicine, has conducted research into around 30 ingredients. He discovered that "gamma oryzanol," a common constituent of brown rice, blocks the ingestion of fat. After successful trials on mice, Masuzaki has now begun trialing gamma oryzanol on humans. His aim is to produce a high-performance food product that also tastes good when sprinkled on simple, light meals.

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Memo: Obesity levels surge across the globe.

According to a 2011 survey by the Organization for Economic Cooperation and Development (OECD), the last 30 years has seen a global upsurge in adult obesity rates. More than 30 percent of all adult Mexicans and U.S. citizens are now obese, for example, while the rate has doubled in Australia and New Zealand since 1990.

Obesity is also a growing problem for developing nations. The World Health Organization (WHO) has reported a doubling of obesity rates in low-income nations over the past 30 years, with women particularly affected. The WHO warns that the world is set to see hundreds of millions more cases of diabetes over the next 20 years as a result.

Obesity is also an issue that impacts children. Obese children are likely to become obese adults and, if left alone, will subsequently be at more risk of developing diabetes or cardiovascular problems.

According to the WHO, there are 43 million "overweight" children aged 5 or under across the world, with over 80 percent of these living in developing nations. To explain this trend, some point to a lack of exercise due to a shortage of safe playing areas, while others blame an over-consumption of fat due to a profusion of cheap, high-calorie foods. In Malaysia, more than 30 percent of all children aged 7 to 9 are classed as "overweight."

Once the number of fat cells (the cause of obesity) increases, it is hard to get rid of them. Childhood obesity in particular is likely to continue into adulthood, with around 70 percent of obese adolescents remaining seriously overweight when they grow up.

Reports also indicate that middle-aged obese people are 2.9 times more at risk from ischemic heart disease than their thinner counterparts. They are also 2.1 times more likely to get colon cancer and 2.2 times more likely to die suddenly.

To deter people from consuming fatty or sugary products, Hungary, the 12th fattest OECD member in terms of adult obesity rates, slapped a "potato chips tax" on salty or sugary snack foods in 2011. New York has also banned fast-food restaurants from using toy giveaways to entice children, while Singapore and South Korea restrict the sale of high-calorie foods near schools as they attempt to curb child obesity.