Increase in Human Size Unprecedented, Study Says (NYT 9/5/11)
For nearly three decades, the Nobel Prize-winning economist Robert Fogel and a small clutch of colleagues have researched what the size and shape of the human body say about economic and social changes throughout history, and vice versa.
Their research has spawned not only a new branch of historical study but also a provocative theory that technology has sped human evolution in an unprecedented way during the past century.
Now Cambridge University Press is publishing the capstone of this inquiry, “The Changing Body: Health, Nutrition, and Human Development in the Western World Since 1700,” just a few weeks shy of Fogel’s 85th birthday.
The book, which sums up the work of dozens of researchers on one of the most ambitious projects undertaken in economic history, is sure to renew debates over Fogel’s groundbreaking theories about what some regard as the most significant development in humanity’s long history.
Fogel and his co-authors — Roderick Floud, Bernard Harris and Sok Chul Hong — maintain that “in most if not quite all parts of the world, the size, shape and longevity of the human body have changed more substantially, and much more rapidly, during the past three centuries than over many previous millennia.” What’s more, they write, this alteration has come about within a time frame that is “minutely short by the standards of Darwinian evolution.”
“The rate of technological and human physiological change in the 20th century has been remarkable,” Fogel said in an phone interview from Chicago, where he is the director of the Center for Population Economics at the University of Chicago’s business school. “Beyond that, a synergy between the improved technology and physiology is more than the simple addition of the two.”
This “technophysio evolution,” powered by advances in food production and public health, has so outpaced traditional evolution, the authors argue, that people today stand apart not just from every other species, but from all previous generations of Homo sapiens as well.
“I don’t know that there is a bigger story in human history than the improvements in health, which include height, weight, disability and longevity,” said Samuel Preston, one of the world’s leading demographers and a sociologist at the University of Pennsylvania.
Without the 20th century’s improvements in nutrition, sanitation and medicine, only half of the current U.S. population would be alive today, he said.
To take just a few examples:
The average adult man in 1850 in America stood about 5 feet 7 inches and weighed about 146 pounds; someone born then was expected to live until about 45. In the 1980s the typical man in his early 30s was about 5 feet 10 inches tall, weighed about 174 pounds and was likely to pass his 75th birthday.
Across the Atlantic, at the time of the French Revolution, a 30-something Frenchman weighed about 110 pounds, compared with 170 pounds now.
And in Norway an average 22-year-old man was about 5½ inches taller at the end of the 20th century (5 feet 10.7 inches) than in the middle of the 18th century (5 feet 5.2 inches).
Fogel and his colleagues’ great achievement was to figure out a way to measure some of that gain in body size, Preston said.
“The Changing Body” is full of statistical tables and graphs that include the heights of girls in Croatia and Germany; the caloric energy derived from potatoes, fish and wine; and the average annual allowance of grains and meat for widows in Middlesex County, Mass., from 1654 to 1799 — a testament to both the staggering accumulation of information and the collaborative nature of the enterprise.
But the basic argument is rather simple: that the health and nutrition of pregnant mothers and their children contribute to the strength and longevity of the next generation. If babies are deprived of sufficient nutrition in the womb and early in life, they will be more fragile and more vulnerable to diseases later.
These weakened adults will, in turn, produce weaker offspring in a self-reinforcing spiral.
Technology rescued humankind from centuries of physical maladies and malnutrition, Fogel argues. Before the 19th century, most people were caught in an endless cycle of subsistence farming.
A colonial-era farmer, for example, worked about 78 hours during a 5½-day week. People needed more food to grow and gain strength, but they were unable to produce more food without being stronger.
One thing Fogel did not expect when he first started his research was that “overnutrition” would become the primary health problem in the United States and other Western nations.