It is a fact that (on average) humans have gotten taller in the last X amount of years. Maybe there are some demographic outliers, but in general humans today are much taller than ancestors of ancient times i.e B.C. and backwards and even in the last 150 years of post-industrialisation we’ve experienced significant height increases.
I’ve read a few different things on the internet - the core reasons given are:
[li]Better nutrition[/li][li]better healthcare[/li][li]genetic mixing due to ease of travel[/li][/ul]
and I’m sure there are lots of other factors. A lot of articles I was reading use the term evolution, but I was always under the impression that evolution only works on longer time scales than a few hundred years.
So to my questions - is there an upper height limit that our genetics/DNA/whatever are limited to?
If there is not, are we expecting humans to grow and grow more, on average? and what is the new average going to be in time n + x years?
I’m relatively tall, and I’m attracted to tall women. My fiance is nearly 6ft. Our kids will therefore likely be tall, and if they also marry tall people and have kids etc then will that drive us towards really large averages in the future?
The tall would have to procreate more to have more tall children in the gene pool. Basically unless people with trait X have more kids who grow up and themselves procreate successfully, I don’t see why that trait would spread in the gene pool. If anything (if current trends continue) we may get shorter overall because Sub Saharan Africa is where all the population growth is occurring. Western nations where being 6’ is not uncommon are seeing their populations decline, while Africa’s will quadruple this century (by the end of this century, about 30-40% of humanity will live in Africa). I think blacks in the US are about as tall as whites and if Africa develops western levels of nutrition I’m assuming their height will match that in the west, but due to the current malnutrition in Africa I’m sure height there will be lower.
Most of it is better nutrition, that is my understanding. But there could be some social/economic factors too.
Actually, even before you get to “your body is unable to support itself” you start having other problems. The very tall have a tendency to drop dead relatively early from heart problems, for example.
Also, pre-agriculture healthy hunter-gatherers were pretty close to today’s average heights.
Better health and nutrition don’t make people taller, it allows them to reach their maximum height dictated by their genes. If you come from genetically short-statured people the best environment in the world still won’t result in you growing up into a giant.
As a point of reference - I remember reading that 2nd generation Japanese-Americans were 2-3" taller than their equals in Japan. Japan was not a 3rd world country before or after WWll. Could nutrition levels in the US be that much better than Japan?
Before WWII the lower classes in Japan ate a diet based mainly on rice - there may have been issues with lack of some nutrients rather than lack of calories. During WWII, especially towards the end of it, and for some years after there were some serious food shortages. Again, there were probably also problems with adequate nutrients as well as calories.
It wasn’t until the '60’s or ‘70’s that the average Japanese diet started to catch up nutrition-wise with the rest of the world. Modern Japanese are also taller than their parents’ generation, too.
My mother’s family was the starkest example of that. Twelve children born in pre-WWII to maybe early post-WWII Japan. Initially very poor family as my grandfather was what we would call a share-cropper. The first born children are incredibly short. My mother was 4’11" and her older sibling was inches shorter.
But post-WWII financial circumstances improved a lot and the younger children are noticeably taller.
This cannot be over-emphasized. The premise of the op is incorrect. Height in ancient times was on average pretty much what it is now. 1600s to 1800s were notably low. What’s been seen is a recovery from early 1900s on pretty much back to baselines. Nutrition and disease impacts on youth were pretty harsh in those centuries in particular, worse than even most of the Middle Ages.
And genetic selection can have an impact even in fairly short time frames. Case study: the Dutch. On average possibly the tallest popualation around but two centuries ago were among the shortest. Average up 8 inches in 150 years. Not all nutrition.