A simple eating rule, common in Japan and other Asian countries, could be the secret to shedding those extra pounds. The principle of 'Hara hachi bun me', which translates to 'eat until you are eight parts full', encourages individuals to stop eating when they feel 80% full.

This approach focuses more on portion control rather than the type of food consumed. This straightforward method of calorie restriction could significantly aid weight loss and even boost overall health under certain conditions. The practice is particularly prevalent on the Japanese island of Okinawa, renowned for its inhabitants' longevity and high quality of life.

Thanks to this dietary guideline, it's believed that Okinawans historically consumed just up to 1,900 calories per day. This resulted in notably lower BMI in older residents compared to their counterparts worldwide.

The principle aligns with standard weight loss advice from the NHS, which recommends a daily calorie reduction of approximately 600kcal for steady, healthy weight loss.

In practical terms, this would mean men requiring around 2,500 calories a day should limit their intake to no more than 1,900kcal, while women needing an average of 2,000 calories a day should consume no more than 1,400 kcal daily.

Does the 80% rule really work?

One study  involving 330 men who adhered to the 80% diet revealed that they consumed fewer calories, averaging around 1997 per day. They also ate less grain-based meals and more vegetable dishes compared to those not following the rule.

The research concluded that men who stuck to the rule had healthier eating habits.

Some studies have suggested that consuming 30% fewer calories than usual can contribute to a longer lifespan and healthy weight loss. This approach helps individuals avoid excessive weight gain and chronic diseases.

For an average healthy individual, reducing calorie intake by this amount has been shown to safely and sustainably aid in losing approximately 0.5 to 1kg per week.

The NHS recommends a balanced diet rich in fruits and vegetables, high fibre foods, and whole grains such as potatoes, brown rice, and wholewheat pasta.

People are also advised to limit their salt intake as it can elevate blood pressure, posing a risk for those medically classified as obese.

Before making any significant changes to your diet with the aim of losing weight, it's crucial to consult a doctor or health professional to ensure you do so safely and healthily. More information and advice on effective weight loss can be found on the NHS website here.