The diet secret that’s key to a longer life

I’M CURRENTLY in Okinawa, a small island off the coast of Japan, filming a series about longevity. Their people are famous for living long, exceptionally healthy lives, mainly thanks to their lifestyle and a strong sense of ‘ikigai’, a Japanese concept that emphasises the importance of focusing on things that give purpose and meaning to your life.

But although Okinawa still has the highest percentage of centenarians in the world, the island is rapidly falling down the life expectancy league tables.

Average life expectancy in Okinawa is now 80 for men and 87 for women. This is close to our own: 80 for men and 84 for women.

Why has there been such a shift? When researchers gathered data on centenarians in Okinawa in the 1960s they found most were slim and energetic and had low rates of chronic illnesses such as heart disease and cancer.

They ate a traditional diet, with lots of vegetables and soy products and small amounts of noodles, rice, pork and fish, while sweet potatoes made up 65 per cent or more of their diet.

Sweet potatoes are rich in fibre, antioxidants, minerals and vitamins.

But the real secret to the Okinawan diet is that it is low in calories; before World War II (when the current generation of centenarians were growing up), the typical Okinawan was eating around 1,700 calories a day, whereas in the UK we are advised to eat 2,000 (for women) and 2,500 (for men) a day. Studies show that a calorie-restricted diet, as long as it is rich in nutrients, is the best way to extend a healthy life. After World War II, the new generation adopted a more Western lifestyle and began to pile on the pounds. The older Okinawans, who stuck to a more traditional way of life, continued to flourish, but for their children and grandchildren the fountain of youth dried up. I prefer a Mediterranean-style diet to an Okinawan diet, but I will be taking a closer look at the health benefits of