EATING less is the key to living longer, with a low-calorie diet the only proven way to prolong life, an expert has revealed.
BBC Scientist Matthew Mosley says that regular fasting holds the secret to living to a ripe old age.
He said: “The bottom line is that calorie restriction is the only thing that’s ever really been shown to prolong life.”
In a new Horizon documentary, Dr Mosley, 55, a qualified doctor who has become the face of popular science on the BBC, reveals compelling evidence about a surprising new key to healthy longevity.
And that is to simply cut down on the amount we eat forever.
Earlier this year, he challenged Britain’s gym culture by showing that small bursts of intense exercise is just as effective as pounding the treadmill three times a week.
Moving on from that, he wanted to see how science can help people stay fit for longer and looked to 101-year-old marathon runner Fauja Singh for answers.
Speaking to the Radio Times, Dr Mosley said: “What’s immediately striking about him is that he’s very skinny but very fit.
“‘He’s 5ft 8in and weighs just over eight stone. He eats a calorie-light, vegetable and plant-based diet that still sustains him for his physical activity. Eating relatively low amounts is a good thing.”
Japan’s Okinawa population are one of a number of communities across the world which follow low-calorie diets and live far longer than the global average.
Tests on animals including fish, rodents and dogs have shown that calorie restriction seemingly increases both their average and maximum lifespan.
Dr Mosley said: “Ultimately, ageing is a product of a high metabolic rate, which in turn increases the number of free radicals we consume. If you stress the body out by restricting calories or fasting, this seems to cause it to adapt and slow the metabolism down. It’s a version of what doesn’t kill you makes you stronger.”
As part of his research for the programme, Dr Mosley visited a devotee of calorie restriction in the USA.
He told the magazine: “For ten years he’s lived on 1,600 calories a day, almost a thousand less than the daily recommended requirement for adult males, and at 5ft 9in he weighs nine-and-a-half stone – he was originally 13 stone.
“He’s in great shape; he has a low body-fat composition and his arteries are pristine. He was a compelling example of the way calorie restriction can improve overall health.”
Dr Mosley has also discovered that occasional fasting can offer some of the benefits of permanent calorie restriction.
This centres around the hormone IGF-1 which is similar to insulin and plays an important role in childhood growth.
Low levels stunt growth, while high levels contribute to cancer and ageing.
Studies have shown that IGF-1 can be restricted in adults by fasting as long as the amount of protein eaten is cut at the same time.
For the programme, Dr Mosley fasted for three and a half days and said he learnt that he could control his hunger and that eating was often more because of habit rather than actual need.
Previous research has shown that cutting calorie intake by around 60 per cent, while maintaining vitamins, minerals and other essential nutrients, can prolong life by up to 40 per cent.
It is also thought to slash the risk of developing cancer, heart dsease, diabetes and stroke, while staving off age-related degeneration of the brain and nervous system.
An extra-low calorie diet is believed to reduce the damage to cells caused by compounds known as free radicals.
These compounds have been linked to heart disease, cancer and Alzheimer’s disease but can be neutralised by the antioxidants found in healthy foods.