Health and Prosperity of Nations: Does Wealth Create Healthier Lives?

Published 15 August 2026 · By Ajay Devalia, NHS Biomedical Scientist and founder of Azenue · Approximately 12-minute read

The short answer: Wealth substantially improves health when countries are developing, but among richer nations, additional GDP does not automatically create longer or healthier lives. Countries such as Japan, Spain and Italy appear to convert their economic resources into longevity more efficiently than some wealthier nations.

We usually measure the wealth of nations through GDP. But GDP tells us how much an economy produces, not necessarily how well its people live.

This exploratory analysis compares 20 countries using internationally available evidence on life expectancy, healthy life expectancy, prosperity, diet, obesity, productivity and sleep.

The central question is simple:

How effectively does a country turn its wealth, food, time and knowledge into healthy human life?

The evidence suggests that prosperity matters enormously. However, once basic security, nutrition, sanitation and healthcare have been established, the relationship becomes more complicated. Greater wealth can coexist with obesity, insufficient sleep, preventable illness and shorter lives.

Contents

1. How the countries were compared
2. Twenty-country comparison
3. Does greater wealth create longer lives?
4. Diet quality, calories and ultra-processed food
5. Sleep, productivity and the limitations of national data
6. The wealthy-nation paradox
7. A Healthy Life Prosperity Index
8. What healthier nations may teach us
9. Frequently asked questions

1. How the countries were compared

I reviewed the latest broadly comparable sources available as of 15 August 2026, prioritising the World Health Organization, World Bank, FAOSTAT, OECD and United Nations Development Programme.

Not every measure is equally reliable. Life expectancy and GDP are measured relatively consistently, while national sleep quality and ultra-processed-food consumption are not.

Methodology note: Source years differ between indicators, so figures are rounded to avoid false precision. This comparison identifies patterns and hypotheses; it does not establish that one national characteristic causes another.

2. Twenty-country comparison

The table concentrates on measures that can be compared reasonably across countries. GDP is adjusted for purchasing power parity (PPP), which is more useful than market exchange rates when comparing living standards. Figures are approximate and should not be treated as a new epidemiological dataset.

Important: Values are rounded analytical comparison figures based on different source years. They are intended to show broad patterns, not provide clinical or investment-grade country rankings.

3. Does greater wealth create longer lives?

At low and middle incomes, greater prosperity can transform health. It supports food security, clean water, housing, sanitation, education, vaccination and access to medical care.

Among wealthy nations, however, the curve appears to flatten. More GDP does not automatically deliver the same increase in healthy years.

Japan, Spain and Italy are especially interesting because their longevity compares favourably with countries that produce considerably more wealth per person. This does not prove that any one diet or behaviour caused the difference. It shows that GDP alone is incomplete.

4. Diet quality matters more than caloric abundance

The United States has one of the highest food-energy supplies in this comparison. Japan has considerably less available food energy, yet substantially longer life expectancy.

More food does not necessarily mean better food & better food cannot be measured by calories alone.

A meaningful national diet measure should examine fruit, vegetables, legumes, whole grains, fibre, free sugar and the extent to which ultra-processed products displace minimally processed foods.

The WHO recommends that people over the age of 10 consume at least 400 grams of fruit and vegetables and at least 25 grams of naturally occurring dietary fibre per day. It also recommends limiting free sugars to below 10% of total energy intake, with a further reduction offering additional benefits. See the WHO healthy diet guidance.

The ultra-processed-food question

Research has reported high ultra-processed-food exposure in countries including the UK and US. Larger reviews have also found associations between higher exposure and several adverse health outcomes.

But that evidence must be communicated carefully. It would be inaccurate to say that ultra-processed food alone explains why one country lives longer than another. National differences in healthcare, income, housing, activity, smoking, education and many other factors operate simultaneously.

5. Sleep changes the story but the data remain limited

Sleep is scientifically important but statistically frustrating. International studies often combine different survey questions, wearable devices, age groups and sampling methods. A group of voluntary wearable users cannot automatically represent a whole country.

For that reason, I would not publish a 1–20 national sleep league table. It would create false precision.

Singapore provides an interesting example. It combines very high prosperity, long life expectancy and comparatively low obesity, while some wearable research suggests shorter sleep among the people sampled. Japan creates a related puzzle.

This does not undermine the importance of adequate sleep. It reminds us that population health is multifactorial.

Sleep and the economy

At population level, insufficient sleep may interact with absenteeism, presenteeism, errors, accidents, chronic illness, healthcare use and labour participation. Sleep is therefore more than a private lifestyle concern.

Working longer is also not the same as producing more. The OECD measures labour productivity through output generated per hour worked. A prosperous society should not necessarily aim to maximise the amount of life spent working; it should consider the value created during that time and whether people retain enough time to recover and live.

6. The wealthy-nation paradox

United States

The United States combines exceptional GDP, technology, productivity and healthcare expenditure with lower life expectancy and higher obesity than several less-rich countries in this comparison.

United Kingdom

The UK presents a milder version. It is a prosperous country with sophisticated health services, yet its longevity and preventable-health outcomes leave room for improvement.

Countries punching above their economic weight

• Spain: exceptional longevity relative to income.
• Italy: similarly strong longevity without Scandinavian or US income levels.
• Japan: very high longevity and low obesity with more modest GDP per person than the richest economies.

These countries may teach us more about health conversion efficiency: how effectively economic resources become healthy years.

7. A proposed Healthy Life Prosperity Index

GDP is a means to human flourishing, not human flourishing itself. A broader 100-point index could include:

Notice that GDP per person would contribute only part of the material-prosperity category—not dominate the entire measure.

An exploratory Health Conversion Efficiency measure

This raw ratio would need statistical adjustment so that lower-income countries do not automatically appear more efficient. It is proposed as a research question, not an established economic or health index.

The more complete measure would ask:

• How long do people live?
• How many of those years are healthy?
• How economically secure are they?
• Do they have enough time to sleep, recover and live?
• Does their environment make healthier choices realistic?
• How equally are those benefits distributed?

8. What healthier nations may teach us

The lesson is not “copy Japan” or “everyone should eat like Italians”. Different countries have different histories, cultures, inequalities and health systems.

The broader lesson is that a high-performing society should make healthier behaviour easier:

• whole foods should be normal rather than exceptional;
• walking and movement should occur naturally;
• people should have time to sleep and recover;
• preventive healthcare should begin early;
• economic productivity should not require continuously extending working time.

Instead of telling people simply to “sleep eight hours”, we should also ask why their work, housing, caring responsibilities or wider environment may make sufficient sleep difficult.

The central conclusion

Greater prosperity initially brings dramatic improvements in food security, sanitation, housing, education, medicine and longevity.

Beyond a certain level, however, additional GDP stops translating automatically into additional healthy years. Food abundance can coexist with poor diet quality. Technology can coexist with inactivity. High productivity can coexist with inadequate recovery. Excellent medical care can coexist with preventable disease.

The better question is therefore not only:

“How rich is this country?”

It is:

“How effectively does this country convert its wealth, food, time and knowledge into healthy human life?”

GDP measures the wealth of an economy. Healthy life measures the wealth of a life.

Frequently asked questions

Does a richer country always have a higher life expectancy?

No. Wealth generally improves health, particularly at lower income levels, but the relationship weakens among high-income countries. Healthcare access, prevention, diet, inequality, environment and lifestyle also matter.

Which countries convert prosperity into longevity effectively?

Japan, Spain and Italy are particularly interesting because they achieve high life expectancy without having the highest GDP per person in this comparison.

Does eating more calories make a population healthier?

Not once adequate nutrition is available. Food quality, dietary balance, fibre, processing and metabolic health are more informative than calorie availability alone.

Can countries be ranked accurately by average sleep?

Not yet with confidence. International sleep datasets often use different surveys, devices and population samples, making a precise global league table potentially misleading.

What is healthy life expectancy?

Healthy life expectancy estimates how many years a person can expect to live in good health, rather than measuring lifespan alone.

Sources and further reading

• WHO Global Health Observatory
• WHO: Healthy diet
• WHO: Obesity and overweight
• World Bank: Life expectancy at birth
• World Bank: GDP per capita, PPP
• FAOSTAT Food Balances
• UNDP Human Development Data Center
• OECD health status data
• OECD labour productivity data

About the author: Ajay Devalia is an NHS Biomedical Scientist and founder of Azenue. He writes about sleep, sustainable wellbeing and the relationship between everyday environments and human health. This independent analysis represents his personal research and not the views of his employer.

At Azenue, our interest begins with one of the environments that shapes everyday wellbeing: the place where we sleep. Explore more practical ideas about sleep, comfort and sustainable living in the Azenue journal.