Residents of Okinawa, the southernmost prefecture of Japan, are famed for their long life expectancy, high numbers of centenarians, and accompanying low risk of age-associated diseases. Much of the longevity advantage in Okinawa is thought to derive from the region’s traditional diet. According to an article published in the Journal of the American College of Nutrition, the Okinawa diet is “low in calories yet nutritionally dense, especially with regard to phytonutrients in the form of antioxidants and flavonoids.”
Phytonutrients are plant chemicals and flavonoids are potent antioxidants with anti-inflammatory and immune system benefits.
Antioxidants are substances that may reduce the risk of many diseases (including heart disease and certain cancers).
Fruit and veg are loaded with antioxidants and the Okinawa diet emphasises these dietary components.
In fact, research suggests that diets associated with a reduced risk of chronic diseases are similar to the traditional Okinawan diet, that is, vegetable and fruit heavy (therefore phytonutrient and antioxidant rich) but reduced in meat, refined grains, saturated fat, sugar, salt, and full-fat dairy products.
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Many of the characteristics of the diet in Okinawa are shared with other healthy dietary patterns, such as the traditional Mediterranean diet or the modern DASH (Dietary Approaches to Stop Hypertension) diet.
“Features such as the low levels of saturated fat, high antioxidant intake, and low glycemic load in these diets are likely contributing to a decreased risk for cardiovascular disease, some cancers, and other chronic diseases through multiple mechanisms, including reduced oxidative stress,” states the journal article.
Research conducted into the specific features of the Okinawa diet suggests the low calorie aspect of the diet may play a key role in the longevity association.
The study investigated six decades of archived population data on the elderly cohort of Okinawans (aged 65-plus) for evidence of calorie restriction.
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Calorie restriction means reducing average daily caloric intake below what is typical or habitual, without malnutrition or deprivation of essential nutrients.
Analyses included traditional diet composition, energy intake, energy expenditure.
The researchers found that low calorie intake correlated with little weight gain with age, life-long low body mass index (BMI) and low risk for mortality from age-related diseases.
How the diet compares to Western equivalents
A comparison of the nutrient profiles of different dietary patterns shows that the traditional Okinawan diet is comparatively lower in fat intake, particularly in terms of saturated fat, and highest in carbohydrate intake, in keeping with the very high intake of antioxidant-rich yet calorie-poor orange-yellow root vegetables, such as sweet potatoes, and green leafy vegetables.
Calorie restriction diets – key considerations
Limiting your calorie intake can evidently confer health benefits but following a very low calorie diet is not for everyone.
A very low calorie diet is a clinically supervised diet plan that involves eating about 800 calories a day or fewer.
According to the NHS, very low calorie diets are for adults who are obese and severely obese, defined as having a BMI over 30 and 40, and need to quickly lose weight.
The body mass index (BMI) is a measure that uses your height and weight to work out if your weight is healthy.
“The diets are not the first option to manage obesity and should not be routinely used,” warns the NHS.
As the health body explains, very low calorie diets should only be followed under medical supervision for a maximum of 12 weeks.
“Do not follow a very low calorie diet unless a GP has suggested it to you,” warns the health body.
Nonetheless, see a GP if you think a very low calorie diet may benefit you, it adds.