I think there are a few things to be said about height. However, I think it's not as useful a metric as people imagine.
Anyway … it's likely connected with the amount of protein available in the diet. Dr. Cate Shanahan — one of the most interesting and well-informed voices in the Ancestral Health space and who qualified as a biochemist as well as a doctor has an interesting table in this book:
Deep Nutrition: Why Your Genes Need Traditional Food: Catherine Shanahan, Luke Shanahan: 9780615228389: Amazon.com: Books
It graphs the increase in height of the Japanese population over a few decades. That correlates with the increase in protein available in the diet, and that probably is no accident. I think Dr. Cate has guested as a columnist on Mark's site. She's definitely worth listening to at any rate.
In the 1970s people used to laugh indulgently at the very gutsy but terribly small Japanese rugby team. A Welsh comedian used to sing:
Tommy David very big man,
None like him out in Japan.
When we find we could not stop,
We give him — whack — karate chop …
There were lines about fitting "platform boots" to the Second Row forwards, and making a nine-foot outside-half with "plastic surgery", too.
I doubt the Japanese players are very much shorter now.
However, as I say, I think height is a measurement of limited value. There's also width of body (shoulders and so on) — and sheer circumference of bones. There seems to be a certain amount of evidence that excessive consumption of refined carbohydrate can cause children to grow fast, but unevenly and in a "long and thin" way.
This has been suggested as long ago as the 1950s:
Splendid Specimens: The History of Nutrition in Bodybuilding - Weston A Price Foundationis articles went into surprising detail on the biochemical pathways through which sugar did its damage, pointing out the relation between sugar and atherosclerosis, abnormal increases in height and weight and skeletal anomalies.
Well … longer ago. Elongation of the bodies and faces of cats, so that the cats were longer but less robust with improper feeding, was noted by Francis Pottenger somewhat earlier:
Pottenger's Cats: A Study in Nutrition: Francis Marion Pottenger Jr.: 9780916764067: Amazon.com: Books
And there's stuff in Weston Price that probably points in the same direction.
Have you ever read Salinger's The Catcher in the Rye?
The Catcher in the Rye: J.D. Salinger: 9780316769488: Amazon.com: Books
A clever book. There's a kind of moral point to it I hadn't really seen that a clergyman explained to me, and I'm sure he must be right. Anyway his reading was this: the boy says "catch" although Burns actually has "meet":
This man said to me that he thought the writer had the boy spending the whole novel trying to catch people out — that's the way he thinks — so that he never really meets anyone.Gin a body meet a body
Comin thro' the rye,
But that's by the by. Notice, for the purposes of this post, how that character is very tall, but also very thin and with glasses. He has also had trouble with tuberculosis, as I recall. There are deep connections here. IIRC, Sally Fallon of the WAPF has spoken of height together with "skinniness", poor eyesight, and malformed jaws (how many people in modern societies have fully-erupted wisdom-teeth?) as being "an American syndrome".
Dr. Cate also has some interesting stuff in the book cited earlier on the gradual blunting of sexual dimorphism that seems to be taking place on industrialised diets. Apparently, a lot of young women are noticeably narrower across the hips — they don't really have a "feminine" shape — this, of course, is a bad thing, because it means delivery after pregnancy will be more difficult for them and Caesarean section, with the attendant disadvantages, more likely needed.