Eat your potatoes and grow big and strong
By Purdy, Director of Publicity, OUP USA
As a proud potato-eater of Irish descent, I was often told by my grandmother Rafferty, “Eat all your potatoes if you want to grow tall and strong.” It seems my grandmother was on to something. Between 1000 and 1900, world population grew from under 300 million to 1.6 billion, and the share of population living in urban areas more than quadrupled, increasing from two to over nine percent. The increase in population accelerated dramatically over time and occurred almost entirely towards the end of the period. Many demographers, historians, and economists alike have speculated as to the reasons for such growth on a global scale. The authors of an article published in The Quarterly Journal of Economics, Nathan Nunn and Nancy Qian, argue that perhaps the potato holds the answer.
“Potatoes provide more calories, vitamins and nutrients per area of land sown than other staple crops. Potatoes dramatically improved agricultural productivity, and provided more calories and nutrients relative to pre-existing Old World staples,” notes Nathan Nunn, Assistant Professor of Economics at Harvard University. “Old World regions that were suitable for potato cultivation experienced larger increases in population and urbanization after the introduction of potatoes.”
The estimates are robust to a number of sensitivity checks, which include controlling for a large number of alternative determinants of population and economic growth. These include legal origin, identity of the colonizer, the prevalence of disease (measured as distance from the equator and potential prevalence of malaria), distance from the coast, a history of Roman rule, the prevalence of Protestantism, being an Atlantic trader, and the historic volume of the slave exports.
“Baseline estimates suggest that the potato accounts for approximately 25-26% of the increase in total population and 27-34% of the increase in urbanization in the period studied,” said Nancy Qian, Assistant Professor of Economics at Yale University. “Estimates suggest that for villages that were fully suitable for potato cultivation, the introduction of the potato increased average adult heights by approximately one-half inch.”
According to the article, findings contribute to the historical debate about the importance of nutritional improvements in explaining part of the rapid population increase over the past three centuries. Furthermore, since urbanization rates and adult heights provide reasonable proxies for economic development and overall standards of living, the results suggest that the availability of potatoes also played an important role in spurring economic growth in the 18th and 19th centuries.
The statistics and figures above have been provided courtesy of The Quarterly Journal of Economics. To read the full article for free online, click here.