The theory: Based on the inhabitants of the Japanese islands of Okinawa, where people live long and relatively disease-free lives, the ‘Okinawa principle’ follows a simple 80/20 approach to the amount of food you eat: Eat until you’re 80% full because it takes 20 minutes for your brain to register that you’re full.

For: “Eating a low-calorie or calorie-restricted diet has been shown to lower the risk of developing chronic disease and thus slow the ageing process,” says naturopath Sarah Stevens. “Okinawans tend to have a lower body mass index, resulting in a lowered risk of diabetes, heart disease and cancer – three of the biggest causes of death in western countries.”

In Okinawa, there are 34 centenarians per 100,000, compared to an average of only five for most of the west. The people look and act a lot younger than they are and the word ‘retirement’ literally doesn’t exist in the local dialect. Just good genes you say? Apparently not.

“We know it is environmental factors rather than good genes that are primarily responsible for the health and youth of these people, because studies show that when they move to other countries and adopt local diets, they also develop local diseases and other signs of ageing,” says Beare.

Protein Vs Carbs

“It’s the ratio of protein to carbohydrates rather than calories consumed that really matters,” says Professor Stephen Simpson from the University of Sydney. “What we’ve found is if you account for the protein to carb balance effect, the calorie effect disappears.”

Ideally, we should be looking to have around 15 per cent of our diet made up of protein, with the rest carbs and fats, says Dr Simpson.

“We know that high protein, low carbs in the diet is a combination that drives pro-ageing pathways of metabolism,” he says. “Anything over 25 per cent of total energy coming from protein and you’ll eat less, which is great if you want to lose weight, but you’ve got to bear in mind it may come with longer term costs, among which our studies suggest is a greater rate of ageing.”

But reduce your protein consumption too much and you’re likely to overeat, replacing the protein with extra carbs in order to feel full, so you can’t win!

Next: Browse low-fat recipes and see alternative eating plans.

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