London: Want to know the secret to a long and healthy life? All you need to do is to follow a four-step plan: No smoking, regular exercise, not being verweight, and eating a Mediterranean-style diet daily, says a new study.

Researchers claim following these simple steps could "substantially reduce" one's risk of early death. And, this is the first time, they have been able to calculate exactly how many years this lifestyle could add to the average life.

Women in particular stand to gain. They could live for up to 15 more years. But men, too, can extend their lives by 8.5 years, the 25-year study has revealed.

Prof Piet van den Brandt, professor of epidemiology at Holland's Maastricht University, which conducted the research, said, "This is the first time a study has looked at lifestyle and overall dietary intake on life-span.

"Previous studies have looked at specific nutrients and their effects but not diet and lifestyle as a whole. It is also the first to draw a distinction between men and women in the effects of a lifestyle on mortality. It means lifestyle really can have a large impact on whether you die early or not and that seems to be more significant for women than men."

The huge study monitored the lifestyle choices and death rates of 12,000 men and women aged between 55 and 69, reports said.

The participants were assessed at the outset on diet and lifestyle. They were weighed to calculate their body mass index, with anything between 18.5 and 25 deemed as normal and healthy.

Those who did not smoke and who maintained a healthy eight with good diet and exercise were found to maintain much better health as they grew older, the findings revealed.

The team found the risk of death for middle-aged women with a poor starting score was the same as healthy women 15 years older, while men with a low score had the same risk of death as a healthy man 8.5 years older.

Those who stuck to a Mediterranean diet with high levels of vegetables, fruit, nuts, fish and whole grains and a low intake of meat and alcohol did best of all. The diet was "significantly" more related to a lower death rate in women.

Prof van den Brandt added: "Within this diet, nuts, vegetables and alcohol intake had the biggest impact on lower mortality rates."

The study also found that the greatest reduction in premature deaths as a result of a healthier lifestyle came for men and women with low or medium levels of education.

A spokesman for UK's Department of Health said, "We want people to know that by making small changes, they can cut their risk of serious health problems like cancer, heart disease and type 2 diabetes.

"Up to half of all cancers could be prevented by lifestyle changes - eating better, doing more exercise, drinking less and to stop smoking."