Much of this is due to better nutrition, but individual and population-level health factors have had an effect, too.
While the average man is taller than his great-grandfather, the extent to which he is taller varies greatly by region, nutritional status, and other factors.
Average height for men by region
The average height for men varies by region due to health and nutrition.
In 2010, the average American man was 69.3 inches. A century ago, the average American man was 67 inches. Though this marks a growth of more than 2 inches, the rate at which Americans are growing has actually slowed relative to other nations.
In 1896, American men were the third tallest in the world. Since then, they've slid to 37th place in height. This is not because Americans are shrinking; it is because other nations are growing at a more rapid rate while American height growth is slowing.
American heights have stabilized over the past 50 years. Every 20 years, Americans gained about 2 inches on their parents, but today's children will average the same height as their parents. This is largely due to better health and nutrition.
Over the last decades, American children have faced fewer growth-stunting nutritional problems or health issues, and so they have grown taller. Because this improvement in health has persisted for the last 20 years or so, children are no longer growing taller than their parents.
A study published in eLife reports that those nations that have experienced more significant improvements in health and nutrition have also grown taller.
East Asians have seen significant height gains over the last century. Iranian men have grown more than any other men, with height increases averaging 6 inches in this time. In Sub-Saharan Africa, poor nutrition has stunted growth, reversing gains in height over the last 2 decades.
Men born in the Netherlands are the tallest, with heights averaging just under 72 inches. Eastern European men also rank near the top of the list.
Indonesian men are the shortest, with average heights of 62.25 inches. Men from Malawi are a close second, with an average height of just 63 inches. Yemen, Laos, and Madagascar also have some of the shortest men.
In Britain and Australia, men average 70 inches tall. In France, the average man is 69.5 inches. In most cases, female height tracks male height, such that nations with taller men also have taller women.
Women in Guatemala and the Philippines are among the world's shortest, with average heights of 58 inches.
Factors that influence height
Height is 60-80 percent heritable, which means that 60-80 percent of the difference in height between people is due to genetic factors. This suggests that genetics influences the height differences between individuals living in environments that offer quality nutrition and little exposure to disease.
In more challenging conditions, factors such as diet and exposure to disease can significantly affect height.
Factors other than genetics that can affect height include:
Factors that may affect height include premature birth, geographic location, and birth weight.
- Birth weight: Birth weight is the result of many factors, including genetics and nutrition in the womb. It is a significant predictor of height.
- Being born prematurely: Premature babies tend to have a lower birth weight, and prematurity is also an independent factor affecting height. Premature babies may grow into shorter adults.
- Hormones: Hormones affect growth throughout life, and especially during puberty. Hormonal imbalances can make people unusually tall or short.
- Nutrition: Nutrition is a major factor in height. Individuals who have poor nutrition, especially those who do not get enough calcium, vitamin D, and other vitamins and minerals, may not grow as tall.
- Geographic location: There is a significant relationship between geographic location and ethnicity, which is related to height. Beyond this factor, location affects exposure to natural sunlight, a source of vitamin D. Location can also affect access to healthful food, poverty, and overall health.
- Stunted growth: Factors that stunt growth, such as eating disorders, severe illnesses, and exposure to some medications, can cause people to grow less tall than they otherwise would.
Medical conditions that cause extremes in height
Spondyloepiphyseal dysplasias (SED)
SED causes a shorter than average trunk. It's also genetic, but it is often not diagnosed until middle childhood.
Diastrophic dysplasia is a rare genetic form of dwarfism that shortens the calves and forearms.
People with dwarfism may experience a variety of health issues. SED, for example, can cause severe osteoarthritis.
Gigantism is almost always the result of a pituitary tumor, though some rare medical conditions can also cause excessive growth. These include:
- Carney complex
- McCune-Albright syndrome
- multiple endocrine neoplasia type 1
People who are abnormally tall are also at risk of a wide number of health issues. Their excessive size can strain the metabolic system and cause cardiovascular problems, including an enlarged heart.
Weight and height: How they are related and why it matters
Weight and height are connected in terms of health. A healthy body mass index (BMI) involves a greater weight as height increases. This means that one person could be considered severely obese and another could be seriously underweight if they had substantially different heights while weighing the same.
For an average man with a height of 69 inches, a healthy weight is between 128-168 pounds.
People with BMIs that are too low or too high are vulnerable to a wide range of medical conditions, including cardiovascular disease, diabetes, and metabolic syndromes.