Three generations of one East Asian family standing side by side in a sunlit garden, arranged by height — a shorter elderly grandmother, a taller mother, and the tallest grown granddaughter — smiling, quietly showing how average height climbed across the generations.

Growth science · Population trends

Why did Korean and Dutch children get so much taller?

GrowSense Growth Science · Educational, not medical advice

Every claim sourced to peer-reviewed research — see references below

A Dutch grandfather born in the nineteenth century and his modern great-grandson can belong to the same family and still stand a head apart. South Korea changed even faster — in only a few post-war generations, children grew substantially taller than their parents and grandparents. Neither country's genes suddenly changed. What changed is how many children could reach the height already written into them.

This is a secular trend in height: a long-term shift in a population’s average stature across successive birth cohorts. The Netherlands climbed over roughly 150 years; South Korea’s steepest rise came in a few decades of rapid development; China is rising now. And then entertainment industries put an unusually tall, lean, carefully styled few on screen — making the change look even larger than it is. This guide separates the real trend from the televised one.

The reframe that explains all of it. Adult height is a record of cumulative net nutrition — the resources left for growing after the body has paid for fighting infection, inflammation, stress and everything else childhood demands. When childhood becomes biologically easier, more of that budget reaches the growth plate.

It is not one food, one drink, or a genetic upgrade. A population's gene pool changes slowly; Dutch and Korean averages changed fast. That speed is the fingerprint of environment acting on inherited potential — enough food, fewer infections, safer pregnancies, cleaner surroundings, better healthcare, and more equal access to all of it.

And it stops. Once most children already have those conditions, extra wealth adds little height. Both the Dutch and the Koreans have essentially plateaued — which is exactly what the "net nutrition" idea predicts.

1. What a secular trend actually measures

A secular trend is a change in average stature across generations, read from records that survived: children of the same age measured in different decades, military recruit rolls, national growth surveys, school-health examinations, adult height by birth year, and the age at which puberty and menarche arrived.

Height is a uniquely useful record because it captures so many childhood conditions at once. A child’s final stature reflects the cumulative effect of genetics, pregnancy and birth, infant feeding, energy and protein, micronutrients, infection burden, chronic disease, sanitation, healthcare access, stress and puberty timing.[10] That is why economists and epidemiologists treat adult height as a marker of the net nutrition a whole society could give its children — the balance left after the biological bills of illness and hardship were paid.

2. South Korea — the fastest rise on record

Yes, Korean children genuinely became taller. This is measured, not a K-pop illusion. National growth surveys run with the Korean Pediatric Society and Ministry of Health documented major changes across the 1967, 1975, 1985, 1997 and 2005 surveys — large shifts in height, weight and body proportions over about four decades.[2][6] A careful comparison of Korea and Japan found Korean children gained particularly fast in the second half of the twentieth century, changing both the size and the timing of growth.[1] Skeletal research pushes the story back further still, but stresses that the dramatic modern jump tracked improving conditions, not a sudden genetic change.[4]

By the 2005 survey, mean height for 20-year-olds was roughly 174.3 cm (men) and 161.2 cm (women) — far above older historical cohorts at the same ages.[2]

But the rise did not continue forever. Analyses of national health surveys suggest final height slowed or largely plateaued by the early twenty-first century, with young-adult men clustering around the mid-174 cm range and decade-apart surveys often differing only slightly.[3][13] The honest conclusion: Koreans became dramatically taller across the development decades — but it is not true that each new generation is still adding several centimetres today.

3. The Netherlands — the longest rise, now the tallest and flat

The Dutch took the slow road. Mean height climbed from the mid-nineteenth century onward until, by the late twentieth, the Netherlands was one of the tallest populations ever measured. The Fifth Dutch Growth Study put average height at age 21 near 183.8 cm (men) and 170.7 cm (women) — and then found the crucial twist: final height in 2009 was almost unchanged from 1997.[7] The most spectacular upward trend in the world had essentially stopped.

The Dutch story is therefore two things at once: an enormous historical increase, and a modern plateau near the top of the global range. A slight reversal may even be emerging — men born around 2001 measured about 1 cm shorter than those born in 1980 — but that is tangled up with changing population composition and migration, not a loss of “tall genes.”[8]

4. China — real gains, but deeply uneven

China is rising now. National nutrition-and-health surveillance reported that between 2015 and 2020, average height among 6–17-year-olds rose by roughly 1.6 cm in boys and 1.0 cm in girls, alongside better nutrient intake and falling childhood anaemia.[12] Longer-term research shows substantial gains, though the increase has slowed in some highly developed regions since the mid-2000s.

Why one Chinese stereotype is especially unreliable. China is vast, and average growth differs sharply by province, urban versus rural residence, north versus south, household income, ethnic group and birth cohort. A tall actor from Beijing or Shanghai tells you almost nothing about the national average — the country contains many different growth environments at once.

5. What actually drove the rise — the same short list, everywhere

Korea and the Netherlands reached the same outcome by different routes, but the causes overlap almost completely. No single factor explains a secular trend; these worked together.

Which is exactly why trends plateau. Every one of these is a barrier being removed. Once the barriers are gone for most of the population, adding more wealth produces diminishing returns — you cannot keep adding centimetres forever. The Dutch and Korean plateaus suggest both populations now grow near the ceiling their combined genes and environment allow. Genetics still sets that ceiling: height is strongly heritable, but heritability describes differences between individuals in a shared environment — it does not mean environment is powerless, which is precisely how a gene pool that barely moved produced a 20 cm shift.[9]

6. Earlier puberty is not the same as a taller adult

Part of what old school photos show is tempo, not final height. Better nutrition and health tend to shift puberty earlier, so a modern 12-year-old can tower over a 12-year-old from decades ago simply by having entered the growth spurt sooner. South Korean women’s age at menarche fell markedly across twentieth-century birth cohorts — a major tempo shift.[5]

Earlier puberty → taller at a given age → but also earlier growth-plate maturation → which can close growth sooner. A faster start does not automatically mean a taller finish.

A true secular trend has to be read off the whole growth curve — earlier childhood growth, earlier puberty, a stronger spurt, greater pre-pubertal height, and genuinely higher adult stature can each contribute. Korea shows both: a real menarche shift and real gains in adult height. The relationship between puberty timing and final height is unpacked in Does early puberty mean a shorter adult?.

7. Why the screen lies — a real trend, selectively cast

Here is how both things are true at once: the population genuinely got taller, and K-pop, K-dramas, Chinese dramas and fashion show you a sample that was never random.

Entertainment companies don’t draw performers from the national census. They select — hard — for facial appearance, body proportions, thinness, stage presence, styling potential, and height or the appearance of height, then balance a group’s visual composition. The result is selection bias: the Korean men you see on screen average nothing like the mid-170s cm of national surveys, because they were chosen partly for being tall and lean. Watch dozens of tall idols and your mind quietly builds a false average — “most Korean men must be 183–190 cm.” China’s industry, which has borrowed much of Korea’s trainee-and-styling system, produces the same illusion.

The basketball-academy test. If an academy picks 20 children from a city, their average height beats the city's — even though every one of them truly lives there. Entertainment casting works the same way. Because the people are labelled "Korean actors" or "Chinese idols," the brain treats a hand-picked group as a representative sample. That's the availability heuristic: vivid, repeated examples feel far more common than they are. And height is genuinely hard to judge from images — we make systematic errors estimating it from photos, especially against styled camera work.

Even the individuals look taller than they measure. Long-legged, small-headed, narrow-shouldered proportions read as tall; platform shoes and hidden lifts add centimetres; a low camera angle stretches the body; high-waisted, monochrome, vertical styling lengthens the line; shorter members get placed at the edges while tall members anchor the frame; and published “profile heights” are marketing, not measurements — rounded, outdated, or simply optimistic.

8. Can parents reproduce the Korean or Dutch trend for one child?

Not directly — and this is the most important practical point. A secular trend describes what happened when millions of children got broadly better conditions. It is not a home recipe for a fixed number of centimetres.

A child who already has adequate energy and protein, normal vitamin and mineral status, safe housing, good healthcare, a low infection burden and healthy thyroid and growth-hormone function will not grow taller by copying another country’s diet. Correcting a real deficiency can restore lost growth potential; adding food or supplements above adequacy does not push height past a child’s genetic and developmental limits — the same logic covered in Growth supplements that matter and How tall will my child be?.

The real lesson these countries teach isn’t “feed more milk and meat.” It’s protect the whole childhood environment — healthy pregnancy and birth, enough calories and protein, diverse micronutrients, vaccination, medical and dental care, treated chronic illness, good sleep, activity, clean air, and honest growth monitoring so an abnormal velocity is investigated early. Populations grew when barriers fell consistently, from pregnancy through adolescence.

9. The questions this raises

Did Korean children really become taller, or is it just K-pop?

Really taller. National growth surveys show a major secular increase, especially during the rapid-development decades of the late twentieth century.[1][2] K-pop exaggerates a real trend; it didn't invent it.

Are Koreans still shooting up every decade?

Probably not. The rise has slowed substantially, and recent young-adult heights look close to a plateau.[3]

Why are the Dutch so tall — was it the milk?

No single food. Tall genetic potential met strong childhood nutrition, low infection burden, broad healthcare, high sanitation and relatively equal living conditions. Dairy may have contributed as part of a good diet, but ecological associations can't prove one food built a nation's height.[7][11]

Is China getting taller too?

Yes — surveillance and longitudinal studies show meaningful gains, though the pattern varies strongly by region and income group.[12]

Can I give my child this trend at home?

Not as a recipe. Population trends came from removing barriers across whole societies. For an individual child, correcting a genuine deficiency helps; going above adequacy doesn't add height beyond their biology.

Can both things be true — taller population and exaggerating media?

Yes, and they are. Korean and Chinese populations genuinely became taller, and entertainment media make them look even taller than national survey data show.

How this connects to the whole system

A national height trend is the same story as one child’s growth, scaled up: stature is an emergent outcome of many conditions, and the signal is always in how they combine over time — never in one food, one gene or one number. That’s why a bone age, a height percentile or a single meal means little alone, and why a hand-picked television cast means nothing about a country. Growth, whether in a child or a nation, rewards removing barriers steadily and reading the whole picture.

Read your child against their own curve — not a nation or a cast

GrowSense tracks your child's height and velocity on their own timeline, against the right reference for who they are — so the question is "is this child growing well for them?", not "how do they compare to a survey average or a styled idol." An honest picture beats an anxious comparison every time.

Explore GrowSense

The parent takeaway

Whole populations became dramatically taller because childhood became biologically easier — more food, fewer infections, safer pregnancies, better healthcare, shared more equally — and then plateaued once those barriers were mostly gone. It was never one food or a genetic upgrade. Earlier puberty makes modern teenagers look taller at a given age without guaranteeing a taller adult. And the screen amplifies a real trend through selection, styling and camera work.

So when a K-drama or a Chinese series makes an entire country look 185 cm, hold both truths together: the population really did grow — and the cast was chosen. Neither one is the whole story on its own.

References

A. Secular trends — South Korea

  1. Cole TJ, Mori H. Fifty years of child height and weight in Japan and South Korea: contrasting secular trends. Am J Hum Biol. 2018;30(2):e23090. PMID: 28833849.
  2. Moon JS. Secular trends of body sizes in Korean children and adolescents. Korean J Pediatr. 2011;54(11):436–442. PMID: 22253640.
  3. Ryoo NY, Shin HY, Kim JH, et al. Change in the height of Korean children and adolescents: analysis from national growth surveys. Korean J Pediatr. 2015;58(9):336–340. PMID: 26512259.
  4. Shin DH, Oh CS, Kim YS, Hwang YI. Ancient-to-modern secular changes in Korean stature. Am J Phys Anthropol. 2012;147(3):433–442. PMID: 22270697.
  5. Hwang JY, Shin C, Frongillo EA, Shin KR, Jo I. Secular trend in age at menarche for South Korean women born between 1920 and 1986. Ann Hum Biol. 2003;30(4):434–442. PMID: 12881142.
  6. Kim JH, Yun S, Hwang SS, et al. The 2017 Korean National Growth Charts for children and adolescents. Korean J Pediatr. 2018;61(5):135–149. PMID: 29853938.

B. Secular trends — Netherlands

  1. Schönbeck Y, Talma H, van Dommelen P, et al. The world's tallest nation has stopped growing taller: the height of Dutch children from 1955 to 2009. Pediatr Res. 2013;73(3):371–377. PMID: 23222908.
  2. Schönbeck Y, van Dommelen P, HiraSing RA, van Buuren S. Trend in height of Turkish and Moroccan children living in the Netherlands. PLoS One. 2015;10(5):e0124686. PMID: 25938671.

C. Genetics, nutrition and the drivers of height

  1. Jelenkovic A, Sund R, Yokoyama Y, et al. Genetic and environmental influences on adult human height across birth cohorts from 1886 to 1994. eLife. 2016;5:e20320. PMID: 27964777.
  2. Perkins JM, Subramanian SV, Davey Smith G, Özaltin E. Adult height, nutrition, and population health. Nutr Rev. 2016;74(3):149–165. PMID: 26928678.
  3. Grasgruber P, Sebera M, Hrazdíra E, Cacek J, Kalina T. Major correlates of male height: a study of 105 countries. Econ Hum Biol. 2016;21:172–195. PMID: 26948573.

D. National surveys and surveillance (institutional sources)

  1. Korea National Health and Nutrition Examination Survey (KNHANES). Korea Disease Control and Prevention Agency — ongoing national anthropometric and nutrition surveillance.
  2. National Health Commission of the People's Republic of China. National nutrition and health surveillance reporting on child and adolescent height, 2015–2020.
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This article is educational and describes population-level trends, not an individual growth plan. A secular trend explains what happened when millions of children experienced better living conditions — it is not a recipe for adding centimetres to one child. If you are concerned about your own child's growth or growth velocity, speak with a qualified paediatrician rather than comparing them to a national average or a television cast.