Why We're Living Longer
Explaining Long-Term Trends in Health and Longevity (Cambridge University Press, 2012) by Robert Fogel
Visitors to the Netherlands cannot fail to notice that Dutch males are tall. Their average height is 72 inches. In the middle 19th century, it was 64 inches. How did the average rise by eight inches in 150 years?
British working-class males were five inches shorter than upper-class males in 1815. A gap persists today, but it is now just one inch.
In the United States, where white men in the colonial period very quickly achieved modern heights, stature declined from 1820 to 1860, as income distribution became less equal. The heights and wages of common laborers fell relative to those of other groups during this period.
Robert Fogel's new book, Explaining Long-Term Trends in Health and Longevity, explores the reasons for these changes. Fogel, Charles R. Walgreen Distinguished Service Professor of American Institutions, won the Nobel Prize in Economics in 1993 for his work applying economic theory and quantitative methods to explain institutional change. His last book, The Changing Body: Health, Nutrition, and Human Development in the Western World since 1700, won the 2011 PROSE award for economics.
The latest book offers seven chapters on such topics as the reduction in chronic disease in the 20th century, changes in stature and nutrition, the role of famine and malnutrition on European mortality rates, and trends in physiological capital. Newcomers to Fogel's work would be advised to start with the latter chapters, including an interview where he lays out his intellectual preoccupations in personal terms.
Fogel's theory of technophysio evolution holds that a combination of technological advances and physical improvements has produced "a form of human evolution that is biological but not genetic, rapid, culturally transmitted, and not necessarily stable."
As people become bigger - taller and heavier - mainly through higher caloric intake and better nutrition, they become less susceptible to disease and premature death. They also become more fit for productive physical labor, thus advancing the cycle of improvement in human capacity.
Fogel also addresses what he considers common misconceptions about health and longevity, such as the widespread belief that as countries get richer, most of their additional income goes to buy food. This implies that as populations and GDP in countries such as China and India increased, food scarcity would grow worse.
Using time-series data, Fogel finds that the elasticity of food consumption is actually much lower than believed, showing why food has not become scarcer as these countries have grown.
Between 1961 and 2000, the income elasticities of demand for food were roughly the same in China, India, Germany, and Italy. As their economies grew, so did their ability to feed their populations.
In Japan, by contrast, the income elasticity was a fraction of that in those other countries. Despite a rapid rise in per capita income across those four decades, the Japanese spent relatively little of it on food. Their "abstention from caloric gluttony" brought about an increase in life expectancy of about 13 years, Fogel writes.
At the opposite extreme, the "more gluttonous Americans," with the highest elasticity on the table, gained only seven more years of life expectancy, he says.
Fogel contends that humans are capable of living 30 years beyond current life expectancies. Today's undergraduates in the United States should plan to live to 100. However, increases in diabetes and asthma could lead to reverses. "Indeed, everything can be reversed," he notes, "because these are not genetic changes, they are environmental changes."
The methodologies Fogel explicates in this book will surely be used by researchers as they attempt to show how much our widening waistlines cost us in ill health, disability, mortality, and expense. - J. Duncan Moore Jr.
Photo by Chris Strong