Japanese people are not as short as many assume. The average 17-year-old Japanese male stands about 170.8 cm (5’7″), which is shorter than the average in Northern Europe or North America but within a few centimeters of many Southern European countries. The real story is more nuanced than genetics alone: Japanese heights have changed dramatically over the past century, driven largely by diet, and the growth has recently stalled for reasons that tell us a lot about how nutrition shapes a population’s stature.
How Much Japanese Heights Have Changed
In 1900, the average 17-year-old Japanese boy was just 157.9 cm (about 5’2″) and the average girl was 147.0 cm (4’10”). These are numbers that would place them well below almost any modern population. By 2024, boys of the same age had reached 170.8 cm, a gain of nearly 13 cm (5 inches) in just over a century. That kind of shift can’t be explained by genetics, which don’t change meaningfully over a few generations. It points squarely to environment.
The growth wasn’t steady. During World War II, heights actually declined. In 1948, the average 17-year-old boy measured 160.6 cm, a drop of 1.9 cm compared to 1939 averages, reflecting wartime food shortages. After the war, heights climbed rapidly through the economic boom decades, peaking around 1995. Since then, there has been no significant change in nearly 30 years.
Diet Is the Biggest Factor
The postwar height boom in Japan tracks almost perfectly with changes in what people ate, particularly how much milk and animal protein entered the diet. A detailed analysis from Kagawa Junior College examined 30 years of data from 1967 to 1996 and found that among all food groups and nutrients, milk intake had the strongest relationship to height gains in Japanese adolescents. Milk consumption nearly doubled during that window, rising from about 74 grams per day in 1968 to 144 grams per day by 1995.
The findings were surprisingly specific. Multiple regression analysis showed that milk itself, not calcium or animal protein in general, was the factor most closely tied to increased height for both boys and girls at age 17. Calcium’s apparent link to height turned out to be what researchers called a “pseudo-correlation,” driven entirely by its presence in milk rather than acting independently. Animal protein from fish, meat, and eggs also correlated with taller stature, but when the statistical models controlled for other variables, milk alone remained significant.
Meanwhile, carbohydrate-heavy diets worked in the opposite direction. Height correlated negatively with carbohydrate intake, and specifically with rice consumption. Traditional Japanese diets before and during the early 20th century were dominated by rice and vegetables with relatively little dairy or meat. That dietary pattern, while healthy in many respects, didn’t provide the growth signals that drive maximum height during adolescence.
Why the Growth Stopped Around 1995
Japan’s height plateau is one of the more puzzling trends in global growth data. The country’s economy remained strong, healthcare kept improving, and food was abundant. Yet heights simply stopped increasing. Several factors likely contribute. Milk consumption peaked around 1995 and has since stagnated or slightly declined. Dietary patterns shifted again, with younger generations eating differently than those who grew up during the postwar boom. Some researchers also point to rising rates of low birth weight in Japan, driven partly by cultural pressure on pregnant women to limit weight gain, which can affect a child’s growth trajectory from the start.
The plateau stands in sharp contrast to what happened in neighboring South Korea during the same period. South Korean children were substantially shorter than Japanese children in the 1970s and 1980s. But South Korean heights kept climbing through the 1990s and 2000s, eventually surpassing Japanese heights by 3 to 4 cm at all ages by the mid-2000s before plateauing themselves. Between 1965 and 2010, South Korean high school boys gained 12.6 cm in average height while their Japanese counterparts gained only 6.1 cm. South Korea’s later but more aggressive adoption of Western dietary patterns, including high dairy and meat consumption, likely accounts for much of that difference.
Genetics Play a Role, but a Smaller One
Genes do set a range for how tall a person can grow. East Asian populations generally have a somewhat shorter genetic ceiling than, say, Northern European populations like the Dutch or Scandinavians. But genetics explain far less than most people think. The 13 cm that Japanese boys gained in a single century happened with no change in the gene pool. And the fact that South Koreans, who share very similar genetic backgrounds with Japanese people, ended up several centimeters taller highlights how powerfully environment overrides inherited potential.
Researchers studying children’s heights across Japan, South Korea, and China have noted that all three populations were “traditionally shorter than Europeans” but grew taller “in varied patterns” during the 20th century. The differences between these genetically similar populations came down to timing: when each country industrialized, when diets shifted toward more animal protein and dairy, and when economic prosperity reached broad enough segments of the population to affect childhood nutrition at scale. Chinese primary school boys now average taller than both Japanese and South Korean boys of the same age, reflecting China’s more recent but rapid nutritional improvements.
Comparing Japan to the Rest of the World
At roughly 170.8 cm for young men, Japan sits in the middle of the global height distribution. The Netherlands, often cited as the tallest country, averages around 183 cm for adult men. The United States averages about 175-176 cm. But Japan is taller than many countries in Southeast Asia, South America, and parts of Africa. The perception that Japanese people are “so short” often comes from comparison with the tallest populations on Earth, which is a skewed frame of reference.
It’s also worth noting that height varies within Japan. People from northern regions like Hokkaido tend to be somewhat taller than those from southern areas, mirroring a pattern seen globally where populations at higher latitudes are often taller. Urban Japanese tend to be slightly taller than rural Japanese, reflecting differences in access to diverse foods during childhood.
What Actually Determines Your Height
About 60 to 80 percent of height variation between individuals within the same population is genetic. But the variation between populations, and especially the changes within a population over time, are overwhelmingly nutritional. The critical window is childhood and adolescence. Protein intake during growth years, adequate calories, micronutrients like zinc and vitamin D, and the absence of chronic illness or parasitic infection all influence whether someone reaches their genetic potential.
The Japanese experience is actually one of the clearest case studies in how quickly height can change when nutrition improves. A population that averaged 5’2″ for young men in 1900 reached 5’7″ by the end of the century. The researchers who studied this transformation suggested that promoting milk consumption among high school students could push heights even further, since the current plateau appears to reflect dietary stagnation rather than a genetic ceiling. Whether that happens remains to be seen, but the data strongly suggests that Japanese people are not “naturally” short so much as they are a population whose height caught up rapidly with modernization and then leveled off when dietary improvements stalled.