Over the last century and a half or so, humans, as a group, have grown significantly taller,
with men from western, industrialized countries today being on average between 3 and 7 inches
(7-18 cm) taller than their counterparts in the mid-19th century.
So why have humans gotten taller?
There is very strong evidence that this simply comes down to nutrition and the body’s ability
to fully benefit from said nutrition via not getting certain diseases that hinder the absorption
of consumed nutrients.
That the environment is drastically more important than other factors, such as microevolution,
is strongly indicated via looking at human height during times of relative comfort compared
with times of strife.
For example, examination of skeletons over human history has shown that, while there
have been peaks and valleys of average height across different cultures at different times,
from the Stone Age through the beginning of the 19th century there has been little significant
difference in average human height on the whole.
As for the peaks and valleys, during the Black Death (1346-1353), 60% of the European population,
about 50 million people, died quite suddenly, leaving the surviving 40% and their offspring
with greater access to food and less crowded living conditions; together, this contributed
to fewer diseases and better nutrition, and as a result, people during the 15th and 16th
centuries in Europe grew rather tall.
In fact, in England, the average man was only about 1.5 inches (3.81 cm) shorter during
this time compared with the average Englishman today (at about 5’9″ or 175 cm).
Seventeenth century Europe, however, was a mess, with cold winters from the Little Ice
Age limiting crop production, civil war in England, Louis XIV’s expansionary aggression
and the Thirty Years’ War.
As a result, human health and height suffered, with the average Frenchman reaching only about
5’4″ (162 cm).
(Not coincidentally why French men popularized wearing high-heels around this time, a practice
that women would later adopt and men largely abandon, outside of horse riding boots.)
Faring little better during the 18th and early parts of the 19th century, many western Europeans
lived in dirty, disease-ridden slums that prevented them from increasing significantly
in height, with men across Europe in 1850 only reaching, on average, about 5’5″
(165 cm).
Starkly marking the difference proper diet and living conditions can make here is that
19th century English students at the Sandhurst Military Academy (upper class) were on average
a whopping 8.7 inches (22 cm) taller than their compatriots at the Marine Society boys
(lower class).
In the United States, things were quite different, with the average man in 1850 attaining a height
of about 5’7″ (170 cm).
In fact, on average, people in the U.S. remained taller than their European counterparts from
the Revolutionary War through World War II (with a slight dip during the second industrial
revolution).
It is thought that American height dominance during this period was due to having a relatively
resource-rich environment, where, with the largely privately owned agriculture-based
society, many had easier access to a wider variety of nutrition sources than was common
in places like the UK, where a very small percentage of people owned much of the land
being farmed and much higher population densities existed.
(See: Why the Mass Avoidance of Some Business is Called Boycotting)
historical-median-male-heightThings began to change after WWII.
In the last half century or so, the average American height has more or less remained
the same, while post-war Europeans have, on the whole, sprouted like crazy.
In the most extreme case, throughout the 19th century men and women of the Netherlands averaged
roughly 5’5″ (166 cm) for men and 5’1″ (156 cm) for women- relatively short for their
era and region of the world.
Today, the tallest people in the world are found in the Netherlands, where the average
man is just over 6 feet tall (183 cm) and the average woman is nearly 5’7″ (170
cm).
By comparison, American men are 5’9″ (175 cm) on average, and women are 5’4″ (163
cm).
Some believe that the great strides in height made by Western Europeans over Americans can
be attributed to their universal health coverage and other social policies, such as maternity
services and greater parental leave allowing for better practicality of things like breastfeeding
vs. formula fed and, later, more time off work providing extra time for preparing nutritious
meals, rather than relying on fast-food and other quick high-calorie, low nutrition “junk”
foods.
Further, the so-called “over-nutrition” prevalent in the U.S., combined with lack
of physical activity leading to widespread obesity, has also been noted for its negative
effects on growth hormones and metabolism, limiting the ultimate adult height somewhat.
So how high will humans grow with perfect nutrition and health care?
It’s generally thought the Dutch are close to the peak of average human height potential,
at least based on innate genetics, and Americans and others are close to it.
This is probably a good thing as the human body is not adapted well for extreme height,
and those outliers who do tower over the rest of us often suffer from various pains and
other debilities related to their abnormal height as they age.