We all want to live healthier and longer lives so that we can enjoy more time with our loved ones, achieve our life goals, or carry on any other activities that are important to us.
Is there anything at all we can do to prolong our life journey whilst maintaining good health, or should we just wait that fate will decide when it’s time for us the end our journey?
First of all, let’s consider that in most cases “fate” materializes in the form of heart disease, stroke, cancer, chronic respiratory diseases, Alzheimer’s diseases, and diabetes. In fact, these are among the top causes of death globally.  
Why do people develop these diseases? Is it just a matter of bad luck? Is it because of some sort of cosmic roulette that randomly decides whose life journey should be short, and whose instead should be longer? Is it just a matter of pure luck that some people have miserable lives that are ruined by disease, and some other people instead feel good and live their lives in great shape and with good energy?
In order to answer these important questions, researchers from the Harvard T.H. Chan School of Public Health have conducted huge studies  to determine the impact of life style habits on health and life expectancy. Their analysis were conducted using the data generated by two very large observational studies:
- The Nurses’ Health Study (NHS) : This huge study started in 1976 and is now in its third generation. It includes more than 275,000 participants and it’s still enrolling as of today. The study is regularly following-up participants since 1976 and assessing the relationship between health and lifestyle factors, and are among the largest prospective investigations into the risk factors for major chronic diseases in women.
- The Health Professionals Follow-up Study (HPFS) : This study began in 1986 to complement the Nurses’ Health Studies with the objective to evaluate the relationships between nutritional factors to the incidence of serious illnesses such as cancer, heart disease, and other vascular diseases in men.
In other words, the researchers from Harvard looked at data on lifestyle habits and health of a huge number of people over a very long period of time. The analysis summarized below, is based on data from over 78,000 women (from the NHS) from 1980 to 2014, and over 40,000 men (from the HPFS) from 1986 to 2014.
Bear in mind: the findings that you can read below are based on data from over 120,000 participants, including 34 years of data for women, and 28 years of data for men.
These two studies used validated questionnaires to regularly collect data from participants on the following lifestyle variables: diet, physical activity, body weight, smoking, alcohol consumption.
These are among the larger studies ever made on humans to explore the relationship between lifestyle and health. It is important to consider that the findings presented below are not based on assumptions, on studies on animals, or on small human studies. These data were collected from huge cohorts of human beings in their normal life settings, and over a significantly long amount of time.
In other words, the researches continuously collected data from participants about their lifestyle habits following a rigorous scientific protocol, and observed who maintained good health and who developed diseases and ultimately died prematurely. And they did it with over 120,000 people for a period of up to 34 years. Here is what they found.
The Five Keys to a Longer and Healthier Life
- Having an healthy diet: this was assessed based on the reported intake of healthy foods such as vegetables, fruits, nuts, whole grains, healthy fats, and omega-3 fatty acids, and unhealthy foods like red and processed meats, sugar-sweetened beverages, trans fat, and sodium.
- Exercising regularly: at least 30 minutes daily of moderate to vigorous activity.
- Maintaining an healthy weight: this is defined by a body mass index (BMI) of 18.5 – 24.9 (click here to calculate your BMI).
- No smoking.
- Having a moderate alcohol intake: up to 1 drink daily for women, and up to 2 daily for men. This means between 5 and 15 grams of alcohol per day for women, and 5 to 30 grams per day for men. Generally, one drink contains about 14 grams of alcohol, this means about 330ml of regular beer, 150ml of wine, or 45ml of distilled spirits.
The following are the key findings from these huge studies:
“Compared with those who did not incorporate any of these lifestyle factors, THOSE WITH ALL FIVE FACTORS LIVED UP TO 14 YEARS LONGER.” 
If you are in your 20s, the above findings may be not particularly meaningful. But if you are in your 40s, 50s, or older, most likely you would appreciate the value of adding 14 years to your life, that you can use to enjoy more time with your loved ones or doing whatever is meaningful or important to you.
The decisions you make and what you do today and every day can radically transform your life and how you age in the future. Although starting early is ideal, it’s never too late to make a positive change and reap the benefits of a healthier life style.
Of course, you may ask: what’s the purpose of living longer, if life is going to be that of an old and sick person? Does it matter if I live longer when my life is miserable, suffering from serious chronic diseases?
This is a relevant question. In fact, the population of people over age 65 has grown more quickly than other age groups thanks to longer live spans and declining birth rates, however people are living more years in poor health .
This important question about health-span was also investigated by the researchers from Harvard. In another study  based on the same huge data set, the researchers discovered that the above 5 factors not only may contribute to a longer life, but also to a healthier life. In fact, the study found that:
“Women at age 50 who practiced four or five of the healthy habits listed above LIVED ABOUT 34 YEARS FREE OF DIABETES, CARDIOVASCULAR DISEASES, AND CANCER, compared with 24 more disease-free years in women who practiced none of these healthy habits.” 
“Men practicing four or five healthy habits at age 50 LIVED ABOUT 31 YEARS FREE OF CHRONIC DISEASE, compared with 24 years among men who practiced none. Men who were current heavy smokers, and men and women with obesity, had the lowest disease-free life expectancy.” 
These results are extremely meaningful. They mean that if you follow an healthy lifestyle, you can not only live much longer, but you can also live many years more that are free of diseases: 10 more years for women, and 7 years for men, according to these studies.
Dr. Walter Willet is Professor of Epidemiology and Nutrition at the Harvard T.H. Chan School of Public Health and Professor of Medicine at Harvard Medical School. He is a world-renowned researcher, and a lead investigator of the Nurses’ Health Study and Health Professional Follow-Up study presented above. Dr. Willet has received many awards, including the Medal of Honor of the American Cancer Society. In his bestseller book “Eat, Drink, and Be Healthy” he comments on these results using the following very simple words:
Eating well – teamed with keeping your weight in the healthy range, exercising regularly, and not smoking – can prevent 80 percent of heart attacks, 90 percent of type 2 diabetes, and 70 percent of colorectal cancer.  It can also help you avoid stroke, osteoporosis, constipation and other digestive woes, cataracts, and aging-related memory loss or dementia. And the benefits aren’t just for the future. A healthy diet can give you more energy and help you feel good today.From the book “Eat Drink, and Be Healthy – The Harvard Medical School Guide to Healthy Eating”, by Walter C. Willet, MD, DrPH, with Patrick J. Skerrett, Co-Developed with the Harvard T.H. Chan School of Public Health
You might want to pause for a moment and think about these results: the best scientific research in the world provides solid evidence that 80% of heart attacks, 90% of type 2 diabetes, and 70% of colorectal cancer can be prevented with a healthy lifestyle. Remember that these are among the top causes of death globally.
So, is getting sick and dying prematurely only a matter of bad luck? The answer is for you to guess.
Once again please remember that these important large studies and their investigators, including Dr. Willet, are among the most important in the world. These words are not coming from a random expert on YouTube or TikTok, or the trending nutritionist in search of fame on TV, maybe advocating for a new absurd miracle diet or suggesting to avoid at all costs certain type of foods. These researches from Harvard and are based on rigorous science. And, very importantly, they are independent from any political or industry pressures. In other words, they don’t care about selling you anything. Their goal is practicing science to advance world’s knowledge. As a matter of fact, these findings are not making some industries particularly happy, such as meat producers just to make one example. These studies are only reporting science-backed observations with no other type of pressures that may steer their findings in certain directions.
Emerging factors for extending life- and health-span
In addition to the five keys to a healthy life-span presented above, there is growing evidence from research suggesting that some additional factors may play an important role to living longer and healthier:
- Improving sleep quality: Research demonstrates how important sleep is for our physical and our mental health. Sleep deficiency, a condition that occurs if you are sleep deprived for long time, increases the risk of obesity, diabetes, cardiovascular disease, depression, and early death . The guidelines of the American Sleep Association are to sleep seven to nine hours for adults .
- Social connections: Studies provide evidence that having positive social connections helps live longer and healthier. Research on adults 50 years and older found that loneliness and social isolation are associated with a higher risk of disease, disability, and mortality [12,13,14,15]. One study of 11,302 elderly participants found that almost 20% of them met criteria for loneliness  and observed that participants who experienced persistent loneliness had a 57% increased risk of early death compared with those who never experienced loneliness, whilst participants who were socially isolated had a 28% increased risk of early death. Participants who experienced both loneliness and social isolation showed signs of advanced biological aging (e.g., chronic inflammation that can increase the risk of morbidities).
- Having life purpose/meaning. Research found that having a sense of meaning or purpose in life is associated with better sleep, healthier weight, higher physical activity levels, and lower inflammation in some people [16,17].
- Brain stimulation. Keeping the brain active through activities that requires strenuous mental effort like learning a new skill or language may reduce the risk of cognitive decline. Research has also found a strong association of having higher education and engaging in intellectually demanding work with a lower risk of dementia, Alzheimer’s disease, and cognitive impairment. [15,18]
- Intermittent fasting. Animal research shows that caloric restriction over a lifetime, such as with intermittent fasting, increases lifespan . Fasting improves regulation of blood glucose, provides greater stress resistance, and decreases inflammation and production of damaging free radicals. During fasting, cells remove or repair damaged molecules . These effects may prevent the development of chronic disorders including obesity, diabetes, cardiovascular disease, cancer, and neurological decline including Alzheimer’s disease . Other effects of intermittent fasting in animals include better balance and coordination, and improved cognition, specifically with memory. Human studies have found improved insulin sensitivity, lower blood pressure, decreased LDL cholesterol, and weight loss [19,21]. However, human studies and randomized controlled trials on the effects of fasting on aging and longevity are still needed.
Important note: we highly recommend you NOT to undertake any self-started intermittent fasting initiative without previous consultation with your physician.
Lifestyle medicine is an emerging a branch of medicine that focusses on improving health and wellbeing by applying the following 6 pillars (the five keys identified above, plus sleep):
Visit the American College of Lifestyle Medicine for more information.
How can we adopt these healthy habits?
The world needs measures to facilitate the adoption of healthy behaviors that can extend the duration and the quality of live of people, switching the focus from (only) treating to (also) preventing diseases.
One way to address this problem may be through public health efforts and policy changes, such as when helmets were made mandatory for driving motorcycles, or seatbelts for cars, or when tobacco was banned in public indoor areas.
This is not an easy journey. If people start live healthier, food companies are not going to sell as much junk food as they do today. And of course making less money does not make them very happy, despite this is going to save millions of lives.
In the meantime, even if you can’t to change the world, you have the power to change yourself and steer your own habits towards a longer, healthier and more fulfilling life.
 Leading Causes of Death (National Center for Health Statistics)
 The top 10 causes of death (World Health Organization)
 The Nutrition Source: Healthy Longevity
 The Nurses’ Health Study and Nurses’ Health Study II are among the largest investigations into the risk factors for major chronic diseases in women
 Health Professionals Follow-up Study
 Impact of Healthy Lifestyle Factors on Life Expectancies in the US Population
 Healthy lifestyle: 5 keys to a longer life
 The Global Roadmap for Healthy Longevity
 Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study
 The Nutrition Source: Sleep
 Lifestyle Sleep Health
 Associations of Loneliness and Social Isolation With Health Span and Life Span in the U.S. Health and Retirement Study
 Social isolation, loneliness, and all-cause mortality: A cohort study of 35,254 Chinese older adults
 Social isolation, social support, and loneliness and their relationship with cognitive health and dementia
 How can dementia and disability be prevented in older adults: where are we today and where are we going?
 Sense of purpose in life and five health behaviors in older adults
 Sense of purpose in life and inflammation in healthy older adults: A longitudinal study
 Lifestyle interventions to prevent cognitive impairment, dementia and Alzheimer disease
 Effects of Intermittent Fasting on Health, Aging, and Disease
 Impact of intermittent fasting on health and disease processes
 Intermittent Fasting: A Heart Healthy Dietary Pattern?
 Balancing life-style and genomics research for disease prevention