The writer Kingsley Amis once quipped that there was no pleasure worth giving up for the sake of two more years in a geriatric home in Weston-super-Mare.

But for pensioners who have been following a pioneering health regime for the last 35 years, an ascetic lifestyle appears to be the secret of a fit and happy old age.

In 1979, 2,500 men were asked to follow five simple rules – eat well, work out, drink less, keep their weight down and never smoke.

Nearly four decades on, just 25 pensioners have managed to stick to the plan. But they are all far fitter and healthier than the volunteers who gave up. Those who stuck to the plan have dramatically cut their risk of cancer, diabetes, heart-attack, stroke and dementia.

Retired teacher Leighton Jones, 80, rides 35 miles a week around the hills and valleys near his home in Caerphilly, South Wales and walks up to two miles every other day.

"I have followed the healthy steps for many years now and feel pretty fit. Cycling keeps my body fit while scrabble keep the mind fit,” said Grandad Mr Jones. "I do have a beer or wine most nights but I drink in moderation."

Bachelor Ray Grace, 80, also kept up with the regime for 35 years. He travels all over Wales and the West Country refereeing college American football matches and walks and jogs two miles every day near his home in the village of Llanbradach.

He said: "I'll go on as long as I am able to. I've been refereeing for nearly 30 years now and still get a thrill out of it."

"As far as I'm concerned it's been a great success. It has been invaluable for me and I'm pleased to have been part of it.

"I've stuck pretty well to the healthy lifestyle laid down and met with the researchers half a dozen times over the years.”

The volunteers, all from Caerphilly gave researchers regular reports of their physical activity, alcohol consumption, and diet. Their wives and families helped by completing regular food frequency questionnaires.

The recommended physical activity was to walk two or more miles to work each day, cycle 10 or more miles to work each day, or regular "vigorous" exercise.

Every five years the men were re-questioned and re-examined along with their medical records to identify new cases of diabetes, heart disease and strokes.

The researchers found non-smoking, an acceptable BMI, a high fruit and vegetable intake, regular physical activity, and moderate alcohol intake were associated with reductions in the incidence of certain chronic diseases.

Study leader Professor Peter Elwood, of Cardiff University, said: "As a nation, we must wake up to the preventive power of living a healthy life.

"Thirty years ago, only 25 men in our study followed all five of our recommended healthy steps.

"Following these steps did not give them complete protection against disease but the men who developed a disease, did so at a much older age than the men neglectful of their lifestyle.

"The development of heart disease was delayed by up to 12 years, and it was up to around an additional six years before dementia took its grip.

"It shows that following a healthy lifestyle staves off disease and premature death."

The reduction in cases of dementia was welcomed by experts yesterday. Alzheimer's Society Research Communications Manager Clare Walton said: "We have known for some time that what is good for your heart is also good for your head.

"The landmark Caerphilly study, part funded by Alzheimer's Society, showed that healthy living can reduce the chances of dementia by up to 60 per cent." Dementia expert Professor John Gallacher of Cardiff University said: "The Caerphilly Study has made a tremendous contribution to UK Science.

"These are exciting times as we gear-up to do research that will bring significant public benefit, helping older people everywhere to have longer and more satisfying lives."