My root crops (carrots, turnips and beets) are growing better as my soil has improved with time and I am now planning for the sweet potato. There are several vogue diets circulating – the Mediterranean diet; the Esselstyn vegan diet I posted a few weeks ago, and the new Nordic diet (a free Coursera MOOC starts September 2013). So why go back in time to the traditional Okinawan diet with its reliance on the sweet potato?
I was pointed to the Journal of the American College of Nutrition 2009 article titled: “The Okinawan Diet: Health Implications of a Low-Calorie, Nutrient-Dense, Antioxidant-Rich Dietary Pattern Low in
Glycemic Load”. The title tells you much about the diet. Okinawa is a prefecture of Japan whose residents are very long lived and this is attributed to their healthy life style including their traditional diet. The authors compare this diet with the traditional Mediterranean diet and DASH (Dietary Approaches to Stop Hypertension) and note that the traditional Okinawan diet is lowest in fat intake and highest in carbohydrate intake especially of orange-yellow root vegetables primarily the sweet potato, which is also antioxidant rich, and green leafy vegetables.
You probably notice “traditional” surfacing a lot – the authors note that changes in the diet since World War II have been for the worse with younger Okinawans now more prone to obesity and other chronic diseases than older Japanese. A helpful chart shows that in 1949 almost 60% of the calories were from the sweet potato with about 13% from rice and 0% from bread. In 1972 less than 5% was from the sweet potato. Other features of the traditional Okinawan diet are lots of vegetables and legumes (mostly soy); some fish; little meat and dairy, and some alcohol (phew!). The emphasis is on low GI carbohydrates – the sweet potato has a GI of 55 compared with 75 for the Yam and 90 for the Irish potato. The article details other functional components of the traditional diet.
So I was pointed, I read, I converted and have now placed an order for 36 Southern sweet potato slips to be delivered and planted in April.