Five Healthy Habits That Could Boost Life Expectancy by Almost 15 Years Identified in Harvard Study

Updated | Scientists have identified five habits that could extend the average human life span by more than a decade in a major new study.

Researchers at Harvard University investigated how a person's diet, weight, exercise regime, smoking and drinking habits affected their life span in order to understand why adults in the U.S. have a higher mortality rate than the residents of almost all other high-income countries. The team was surprised by how significantly a healthy lifestyle appeared to boost life expectancy.

To make their findings, the team assessed lifestyle questionnaires and medical records from over 123,000 volunteers completed over 34 years. The average life expectancy of participants who followed five healthy habits rose by 12 years in men and 14 years in women, according to the study.

The optimum lifestyle involved a diet low in red meat, sugars and saturated fats, but high in vegetables, fruits and whole grains, and alcohol consumption of no more than 15 grams per day for women, and 30 grams per day for men. It also involved not smoking, maintaining a body mass index between 18.5 and 24.9, and taking at least 30 minutes of moderate exercise a day.

The authors of the study, published in the journal Circulation, found that "adopting a healthy lifestyle could substantially reduce premature mortality and prolong life expectancy in U.S. adults."

Men and women who followed this lifestyle were 82 percent less likely to die of cardiovascular disease on average, and 65 percent less likely to die of cancer, compared with those whose lifestyles were found to be the least healthy.

Meir Stampfer, a coauthor on the study and professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, told The Guardian, "When we embarked on this study, I thought, of course, that people who adopted these habits would live longer. But the surprising thing was how huge the effect was."

Stampfer added that while members of the public must accept responsibility for not following a healthy lifestyle to some extent, society needs to make it easier for people to do so, too. And while people may believe it is too late to change their unhealthy habits, "what we find is that when people do change their ways, we see remarkable benefits," said Stampfer.

Evan Kontopantelis, professor of data science and health services research at the University of Manchester, told Newsweek: "What to take from the study: If you smoke, quit now! This is by far the best thing you can do for your health, your health insurer, and the health system of your country. Try to exercise, don't drink alcohol excessively and have a balanced diet. And these three lifestyle changes will also keep or reduce your BMI within a 'normal' range since exercise can reduce appetite (plus you are not at home, raiding the fridge), and there are lots of calories in alcohol."

Les Mayhew, professor of statistics at London's Cass Business School, told Newsweek that the study is "extremely significant" and adds to the evidence building up from studies around the world.

"If everybody adopted low-risk health behaviors, there would be far fewer inequalities in society, and also huge benefits to the wider economy. We should not forget, however, that many high-risk health behaviors are also linked to economic inequalities and deprivation and so are inseparable."

Professor Sarah Stewart-Brown, chair of public health at Warwick University Medical School, argued that the public likely won't be surprised by the study's findings, but rather the extent to which the five factors raise life expectancy.

"But the study does not address what causes people to live in a way which damages their health," Stewart-Brown told Newsweek. "At one level, these lifestyles appear to be a choice, but at another level, as we all know, smoking, drinking too much alcohol, being a couch potato and eating foods that do us no good are addictive and more compelling when we are feeling low.

"Most of us get through life using one or perhaps two of these props when we are feeling down. To need all five on a ongoing basis indicates a very low level of mental health. Poor mental health means people need these lifestyle props more than those who don't have to cope with such problems. But poor mental health also increases the risk of disease in its own right, because it is stressful, and stress interferes with bodily functioning."

Duane Mellor, qualified dietitian and spokesperson for the British Dietetic Association, agreed that the study is not a surprise, and questioned whether the large number of participants was representative of the U.S. population.

"The size of that effect although estimated from a large population, may not be representative of everyone, as the data this is based on is largely white educated health professionals, and this perhaps means that issues such as poverty, limited life chances and education which have a big role in creating both social and health inequalities were less common in this study," he told Newsweek.

This piece has been updated to include comments from Professor Sarah Stewart-Brown, Professor Evan Kontopantelis​, and Duane Mellor.