Were people smaller 100 years ago?

Were people smaller 100 years ago? Yes, they were. The average young adult today stands about 10 cm (4 inches) taller than someone born a century ago, and this is true for every country on the planet. A 2016 study published in eLife by the NCD Risk Factor Collaboration analyzed over 18.6 million people across 200 countries and confirmed this. The gain is not evolution. It happened way too fast for that. It comes down to food, disease, and living conditions during childhood.

So what exactly made people shorter back then, and what changed? Let’s break it down.

How Much Shorter Were People 100 Years Ago?

People born around 1896 to 1920 were noticeably shorter than people born today. The numbers make it clear.

During World War I, the average British soldier stood about 168 cm (5 feet 6 inches). Today, the average young British man is about 178 cm (5 feet 10 inches). That is a 10 cm jump in roughly four generations.

Some countries saw even bigger gains. South Korean women gained about 20 cm over the century. Iranian men gained about 16.5 cm. European and Central Asian populations saw the largest overall increases and now stand taller than North Americans on average.

The shortest recorded populations a century ago were men in Laos at about 153 cm, which is the same height as a healthy 12 year old boy by today’s growth standards. Women in Guatemala averaged just 140 cm, about the same as a well-nourished 10 year old girl today.

The tallest people alive now? Dutch men, at around 182.5 cm (just over 6 feet). The gap between the tallest and shortest countries was about 20 cm a century ago, and it remains roughly the same today.

Is the Height Increase Caused by Evolution?

No. Evolution works over thousands to millions of years. Humans have a lifespan of about a century, so meaningful evolutionary change in height takes far longer than 100 years. The height gain we see is not genetic change across the species.

The real drivers are environmental. When children get better nutrition and fewer diseases during their growing years, they reach closer to their full genetic height potential. The genes for height were always there. What changed is the conditions that allow those genes to express fully.

According to Scientific American, about 60 to 80 percent of the difference in height between any two people comes down to genetics. The other 20 to 40 percent is environmental, with nutrition being the single biggest factor.

Think of it this way. Your DNA sets the ceiling for how tall you can grow. But if you are sick all the time as a kid, or you do not get enough protein and calcium, you will never reach that ceiling. A hundred years ago, most people never reached it.

What Made People Shorter in the Past?

Three things held people back from reaching their full height. All three were common 100 years ago and all three hit children the hardest.

1. Poor nutrition. Diets were less varied and less protein-rich, especially for working-class families. Protein is the single most important nutrient for reaching full adult height. Calcium, vitamin D, vitamin A, and zinc also matter. Many families a century ago survived on bread, potatoes, and very little meat or dairy. Children needed more nutrients per kilogram of body weight than adults, and they simply were not getting them.
2. Childhood disease. Repeated infections during infancy and childhood slow growth. When a kid gets sick, their body redirects nutrients away from growth and toward fighting the disease. Respiratory infections like pneumonia and bronchitis, and gut infections like dysentery and diarrhea, were everywhere. Children who survived these illnesses often ended up shorter as adults.
3. Bad living conditions. Overcrowded housing, dirty water, poor sewage systems, and lack of basic hygiene all created breeding grounds for disease. Research on World War I servicemen found that those who grew up in areas with high infant mortality (a strong marker of bad living conditions) ended up shorter as adults.

Family size played a role too. Victorian families averaged five children. By the 1930s, that dropped to two. Fewer children meant each child got a bigger share of the food. Researchers found that servicemen with more siblings tended to be shorter, showing a direct tradeoff between family size and growth.

What Nutrients Matter Most for Height?

Protein is the number one nutrient for reaching full adult height. A review published in Scientific American confirmed that protein intake during childhood is the single most important nutritional factor for final height. After that, calcium, vitamin D, and vitamin A round out the top four.

Here is what each one does.

1. Protein provides the amino acids your body needs to build bones, muscles, and tissues during growth spurts. Children need about 0.5 to 1 gram of protein per pound of body weight each day. Good sources include lean meats, fish, eggs, dairy, beans, and nuts.
2. Calcium makes up 98% of your bones. Children aged 4 to 8 need about 1,000 mg of calcium daily. Kids aged 9 to 18 need about 1,300 mg. Up to 90% of peak bone mass is built by age 20, making childhood and teenage years the window that matters most.
3. Vitamin D helps your body absorb calcium and deposit it into bones. Without enough vitamin D, calcium goes to waste. Sunlight triggers vitamin D production in the skin, but diet matters too.
4. Zinc powers dozens of growth-related chemical reactions in the body. It helps regulate development and supports the immune system so kids stay healthy enough to keep growing.

A century ago, most children did not hit their daily requirements for any of these. That is a big reason why populations were shorter.

Did Height Stop Increasing?

In some countries, yes. Height gains have flattened out in many wealthy nations over the last 20 to 30 years.

In the United States, average male height peaked at about 5 feet 10 inches (178 cm) for men born in the mid 1990s. Since then, it has actually dropped by about 0.3 inches. American women peaked at 5 feet 5 inches (165 cm) around 1988 and have not gained since.

The US used to rank third tallest in the world for men and fourth for women back in 1914. Now American men rank 37th and women rank 42nd.

Northern European countries like Finland, Denmark, and the Netherlands have also seen their height increases flatten. Meanwhile, countries in East Asia and parts of Latin America are still getting taller as nutrition and healthcare improve.

Researchers believe height may be approaching a biological ceiling in well-fed, healthy populations. When a country provides good nutrition and low disease rates during childhood, its people reach close to their genetic maximum. After that, there is not much room left to grow.

Does Obesity Affect Height?

This is one of the leading theories for why height has stalled in countries like the US and UK. Childhood obesity and poor diet quality during growth years can limit how tall a child becomes.

The issue is not total calories. Kids in wealthy countries get plenty of calories. The problem is the type of calories. A diet heavy in processed foods, sugar, and saturated fat but low in protein, vitamins, and minerals does not support optimal growth, even if the child is eating more food overall.

A study from the Philippines found that each extra 100 calories a day from a varied, healthy diet led to measurable height increases in children. But those benefits faded for children in higher socioeconomic groups who were already well-fed, and they disappeared entirely when the extra calories came without nutritional quality.

Research in the UK found that lower socioeconomic status correlated with shorter height and higher BMI. The combination of poor diet quality and excess calories can lead to a child who is overweight but still shorter than their genetic potential.

Are We Going to Keep Getting Taller?

Probably not by much in wealthy countries, but the gains are not over worldwide.

In places where childhood nutrition and healthcare are still improving, like parts of Asia, Latin America, and Africa, populations will continue to get taller. The biggest gains happen when a country moves from widespread childhood malnutrition to reliable access to protein-rich food, clean water, and basic healthcare.

For countries that already have these things, the focus shifts to diet quality. Making sure children eat enough protein, calcium, and vitamin-rich foods during their growing years gives them the best shot at reaching their genetic height potential.

Physical activity also matters. Research shows that active children tend to grow taller than sedentary ones. Activities that load the bones, like running, jumping, and resistance training, support bone growth and density. Sleep is another factor. Growth hormone is released in higher amounts during deep sleep, which is why children and teenagers need 9 to 11 hours a night.

What Does This Mean for Your Health Today?

The fact that people are taller now is mostly good news. It means better childhood nutrition, fewer diseases, and improved living standards across the globe. Height tracks population health better than almost any other single measurement.

But the stalling of height in wealthy countries is a warning sign. It signals that diet quality has hit a wall even though food quantity is not a problem. Too many processed calories and not enough real nutrition can hold the next generation back from reaching their full potential.

The fix is not complicated. Feed kids real food with enough protein, calcium, and vitamins during their growing years. Keep them active. Make sure they sleep enough. These are the same things that fueled the height explosion over the last 100 years, and they are still the foundation of healthy growth.

Frequently Asked Questions

How much taller are we than people 100 years ago?

About 10 cm (4 inches) on average worldwide. Some countries gained much more. South Korean women grew about 20 cm taller over the century, and Iranian men gained about 16.5 cm. European populations saw gains of 10 to 14 cm on average.

Why were people shorter 100 years ago?

Three reasons. Poor nutrition meant children did not get enough protein, calcium, or vitamins to grow fully. Childhood diseases like pneumonia and dysentery used up nutrients and stunted growth. Bad living conditions with overcrowding, dirty water, and no sewage systems spread those diseases widely.

Is the height increase caused by genetic evolution?

No. Evolution takes thousands of years. The height changes over the last century are environmental. Better food, cleaner water, fewer childhood diseases, and improved living conditions allowed people to reach more of their genetic height potential.

What is the most important nutrient for growing taller?

Protein. It supplies the building blocks for bones, muscles, and tissues. Calcium, vitamin D, and zinc are also important. Children who do not get enough of these nutrients during their growth years end up shorter than their genetics would allow.

Have we stopped getting taller?

In many wealthy nations, yes. The US, UK, and several Northern European countries have seen height gains flatten or slightly decrease since the 1990s. Countries in East Asia and Latin America are still gaining height as nutrition improves.

Why did Americans stop getting taller?

Several factors. Rising rates of childhood obesity, poor diet quality despite high calorie intake, inequality in access to healthcare, and immigration patterns all play a role. The US dropped from third tallest in 1914 to 37th for men today.

Who are the tallest people in the world today?

Dutch men lead at about 182.5 cm (just over 6 feet). Latvian women are the tallest at about 170 cm (5 feet 7 inches). The shortest populations today are men from Timor-Leste at about 160 cm and women from Guatemala at about 149 cm.

Does exercise help children grow taller?

Yes. Physical activity, especially weight-bearing activities like running, jumping, and resistance training, supports bone growth and density. Active children tend to grow closer to their genetic height potential than sedentary children.

How much of height is genetic vs environmental?

About 60 to 80 percent of height differences between individuals come from genetics. The remaining 20 to 40 percent depends on environment, mainly nutrition during childhood. Your genes set the ceiling, but your diet and health determine whether you reach it.

Can adults increase their height?

No. Once your growth plates close (around age 16 for girls and 18 to 19 for boys), you cannot grow taller. The window for height is childhood and adolescence. After that, the focus shifts to maintaining bone density through exercise, calcium, and vitamin D.

Sudden weight fluctuations can be confusing, especially when following endurance training programs like those used by marathon runners. To put these changes in historical perspective, it’s fascinating to learn whether people were smaller a century ago and how nutrition has evolved. For expert help understanding your body’s responses to training and nutrition, including weight fluctuations, a personal trainer in South Yarra can provide clarity and actionable strategies tailored to your situation.