Lifespan is how long you live; healthspan is how many of those years you spend in good health, free of serious illness and disability. Worldwide, people now spend about a decade of life in poorer health. In WHO's 2023 estimates, the gap was 10.5 years globally and 13.9 years in the United States. Large studies link daily habits, diet among them, with more healthy years.
What is healthspan?
Healthspan is the part of your life lived in good health. Researchers define it in slightly different ways. Some count the years free of major chronic diseases. Others also require good physical function, clear thinking and mental well-being.
The idea matters because longer lives have not brought an equal gain in healthy years. Life expectancy has risen by about three decades since the mid-twentieth century. Healthspan has not kept pace, held back largely by chronic disease in a growing older population (Garmany et al., 2021).
The World Health Organization tracks this with a measure called healthy life expectancy, or HALE. It estimates how many years a newborn can expect to live in full health. The difference between life expectancy and HALE is often called the healthspan-lifespan gap.
Healthspan vs lifespan: how big is the gap?
The table below uses the latest WHO figures, for 2023 (WHO, life expectancy; WHO, HALE). We calculated the gap by subtracting one from the other.
| 2023, at birth | Life expectancy | Healthy life expectancy (HALE) | Years in poorer health |
|---|---|---|---|
| World | 73.3 years | 62.8 years | 10.5 years |
| United States | 78.5 years | 64.6 years | 13.9 years |
| Greece | 81.9 years | 69.8 years | 12.1 years |
A 2024 study looked at the same WHO data across 183 member states over two decades. It found the gap had widened worldwide, reaching 9.6 years. Women's gap was 2.4 years wider than men's on average. The United States had the largest gap of any country, at 12.4 years. The authors tied this to a rise in chronic diseases (Garmany and Terzic, 2024).
The study's figures differ slightly from ours because it used different years and averaged across countries. The message is the same. Many people can expect a decade or more of living with illness or limits on what they can do.
Why do the healthy years matter more?
Most people over 40 do not fear old age itself. They fear the years of it spent unwell: losing mobility, losing independence, or managing several conditions at once.
Two people can both live to 85. One stays active and independent until the last year or two. The other spends the final fifteen years with chronic illness. Their lifespans match. Their healthspans do not.
This is why healthspan has become the more useful goal. It is also something you can influence. You cannot choose your genes, but several of the strongest predictors of healthy years are habits. We make a related case for active people in recovery and longevity are the same conversation.
What predicts a longer healthspan?
Some of the clearest data come from two long-running Harvard cohorts, the Nurses' Health Study and the Health Professionals Follow-Up Study. Researchers tracked more than 110,000 adults for up to 34 years. They looked at five low-risk habits (Li et al., 2020):
- never smoking
- a body mass index between 18.5 and 24.9
- at least 30 minutes a day of moderate to vigorous activity
- moderate alcohol intake (the study's definition, not a recommendation to drink)
- a diet quality score in the top 40%
The outcome was years lived free of diabetes, cardiovascular disease and cancer, starting at age 50.
| Disease-free years from age 50 | No low-risk habits | 4 or 5 low-risk habits | Difference |
|---|---|---|---|
| Women | 23.7 years | 34.4 years | About 10.7 years |
| Men | 23.5 years | 31.1 years | About 7.6 years |
Two groups spent the smallest share of their remaining life free of these diseases: men who smoked 15 or more cigarettes a day, and people with obesity. In both, disease-free years made up 75% or less of their total life expectancy at 50.
An earlier analysis of the same cohorts looked at total lifespan. At age 50, women with all five habits were projected to live 14.0 years longer than women with none. For men, the difference was 12.2 years (Li et al., 2018). Put together, the two studies suggest these habits were linked with more years overall, and with more of those years spent healthy.
These are observational studies. They show associations, not proof of cause. People with healthy habits often differ in income, education and access to care, and researchers can only partly adjust for that.
Where does diet fit into healthspan?
Diet is one of the five habits, and it has been studied on its own.
In the Nurses' Health Study, researchers rated the diets of 10,670 women in their late 50s and early 60s. They checked their health about 15 years later. "Healthy aging" meant reaching 70 or older without major chronic disease and with good physical, cognitive and mental health. Women in the top fifth for Mediterranean diet adherence had 46% greater odds of healthy aging than those in the bottom fifth (Samieri et al., 2013).
A larger 2025 study followed 105,015 adults for up to 30 years. Only 9.3% met its strict definition of healthy aging. For all eight dietary patterns tested, higher adherence was linked with greater odds of healthy aging. The odds ratios for the top versus bottom fifth ranged from 1.45 to 1.86 (Tessier et al., 2025).
The same study named specific foods. Higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes and low-fat dairy were linked to greater odds of healthy aging. Higher intakes of trans fats, sodium, sugary drinks and red or processed meat were linked to lower odds.
Olive oil fits here as the main source of unsaturated fat in a Mediterranean pattern. The same Harvard cohorts were followed for 28 years. People who used more than half a tablespoon (7 g) a day had a 19% lower rate of death from any cause. The comparison was with people who rarely or never used it. Swapping 10 g a day of butter, margarine, mayonnaise or dairy fat for olive oil was linked with lower mortality. Compared with other vegetable oils combined, there was no significant difference (Guasch-Ferré et al., 2022).
That last point is important. The benefit seen in studies like these comes mostly from what olive oil replaces and the pattern it belongs to. It is not a stand-alone fix. For more on olive oil's role, see olive oil and longevity.
How to protect your healthspan after 40
None of the research points to a secret. It points to steady, unexciting habits kept for years.
- Do not smoke. Heavy smokers had among the fewest disease-free years in the data. If you smoke, ask for help to stop.
- Move most days. The cohort threshold was 30 minutes a day of moderate to vigorous activity.
- Eat mostly plants. Build meals on vegetables, legumes, whole grains, fruit and nuts.
- Use olive oil as your main fat. Use it in place of butter, margarine and creamy dressings, not on top of them.
- Limit the foods linked with poorer aging. Keep processed meat, sugary drinks and salty packaged foods occasional.
- Keep a healthy weight. People with obesity also had among the fewest disease-free years.
Food also works best as part of a whole way of life, with movement, sleep and company at the table. We explore that in why food alone isn't enough. For the full eating pattern, read our pillar guide, eating for longevity after 40.
If olive oil is your everyday fat, Pomoni High-Phenolic Olive Oil is an early-harvest Greek oil measured at 635 mg/kg total polyphenols by HPLC.
Sources
- Garmany A, Yamada S, Terzic A. Longevity leap: mind the healthspan gap. npj Regenerative Medicine. 2021;6(1):57. doi.org/10.1038/s41536-021-00169-5
- Garmany A, Terzic A. Global healthspan-lifespan gaps among 183 World Health Organization member states. JAMA Network Open. 2024;7(12):e2450241. doi.org/10.1001/jamanetworkopen.2024.50241
- World Health Organization. Global Health Observatory: Life expectancy at birth (years). Accessed October 2026. who.int
- World Health Organization. Global Health Observatory: Healthy life expectancy (HALE) at birth (years). Accessed October 2026. who.int
- Li Y, Schoufour J, Wang DD, et al. Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study. BMJ. 2020;368:l6669. doi.org/10.1136/bmj.l6669
- Li Y, Pan A, Wang DD, et al. Impact of healthy lifestyle factors on life expectancies in the US population. Circulation. 2018;138(4):345–355. doi.org/10.1161/CIRCULATIONAHA.117.032047
- Samieri C, Sun Q, Townsend MK, et al. The association between dietary patterns at midlife and health in aging: an observational study. Annals of Internal Medicine. 2013;159(9):584–591. doi.org/10.7326/0003-4819-159-9-201311050-00004
- Tessier AJ, Wang F, Korat AA, et al. Optimal dietary patterns for healthy aging. Nature Medicine. 2025;31(5):1644–1652. doi.org/10.1038/s41591-025-03570-5
- Guasch-Ferré M, Li Y, Willett WC, et al. Consumption of olive oil and risk of total and cause-specific mortality among U.S. adults. Journal of the American College of Cardiology. 2022;79(2):101–112. doi.org/10.1016/j.jacc.2021.10.041
