The tallest men in the world are Dutch, the tallest women are Latvian — and the Americans, which used to be among the world's tallest people, are nowhere near the top 10. Or even the top 30: men from the United States are number 37, and women fare even worse, at number 42.

That's according to a study by the Imperial College of London, which used biometric data collected from 18-year olds around the world between 1914 and 2014. The study showed that on average, American women grew just five centimeters over the century to 163.5 cm — or two inches, to about 5'4'' on average, while men grew about 6 cm, to approximately 177.1 cm or 5'8''. (One centimeter is about 1/4 of an inch.)

Dutch men average at 184.5 cm, or about 6 cm taller than American men, and Latvian women at 172.6 cm, 8 cm taller than their US counterparts.

The biggest growth was seen in South Korean women, who grew an average of 20.2 cm (7.9 in), and Iranian men, whose average height increased by 16.5 cm (6.5in).

(An interactive map of height evolution worldwide can be found here.)

One of the major findings of the study is that some so-called developed nations have fallen in world height rankings. 100 years ago, men in the US were the third-tallest, and women the fourth-tallest, on Earth. That matches drops in other in other highly developed nations such as Japan, the UK and Finland, perhaps because of a rise in obesity.

People in sub-Saharan Africa, North Africa and the Middle East have also seen a marked decline in height over the past three to four decades, a trend that has been associated with challenging nutritional and environmental conditions.

Taller isn't always better, though. Several studies have shown a possible correlation between increased height and increased risk of prostate and ovarian cancer. However, a stagnation or decline in height over the past century is an indication that certain countries in the developed, English-speaking world could do a better job of emphasizing good nutritional standards for their youth.

The study "shows the English-speaking world, especially the USA, is falling behind other high-income nations in Europe and Asia Pacific," professor Majid Ezzati of the college's School of Public Health said. "Together with the poor performance of these countries in terms of obesity, this emphasizes the need for more effective policies towards healthy nutrition throughout life."

One of the most notable growth spurts in human history saw West Europeans shooting upwards during the Industrial Revolution in the 19th century. That jump in height is largely attributed to an increase in agricultural production, urban sanitation, and an overall improvement in nutritional and environmental resources.

John Komlos, professor emeritus of economic history at the University of Munich, says that the stagnation of growth in the USA compared to Northern European populations could be due to different national healthcare systems: for example, the Dutch have access to socialized medicine that Americans do not.

Speaking about a study that he conducted in 2004, Komlos told the BBC that "we think it could be linked to factors such as the better medical attention available in western and northern European countries, and better access to a welfare state. In the face of expensive medical insurance, fewer and fewer Americans are seeing doctors on a regular basis, and cheap fast food has quickly become their most readily available source of nutrition."