The Changing Body, Health, Nutrition, and Human Development in the Western World since 1700
by Roderick Floud, Robert W. Fogel, Bernard Harris and Sok Chul Hong, (Cambridge Press, 2011)
The authors are distinguished economists (Fogel has a Nobel Prize in Economics). With dizzying detail, it traces the changes in the human body over the last 300 years in Britain, France and the United States. During this period, humans have become much taller and heavier than ever before. The book charts the “technophysio evolution,” a complex interplay between increasing technological changes and improved standards of living, resulting in improved nutrition. The improved nutrition is passed from mother to child to child with improvements in height and weight in successive generations. This is not a straight line but the trends are unmistakable – improved mortality with tall and heavier adults.
The Technophysio Evolution hypothesis has five elements:
- The nutritional status of a generation – shown by the size and shape of their bodies – determines how long that generation will live and how much work its members will be able to do.
- The work of a generation, measured both in hours, days, and weeks of work and in work intensity, when combined with the available technology, determines the output of that generation in terms of goods and services.
- The output of a generation is partly determined by its inheritance from past generations; it also determines its standard of living and its distribution of income and wealth, together with the investment it makes in technology.
- The standard of living of a generation determines, through its fertility and distribution of income and wealth, the nutritional status of the next generation.
- And so on, ad infinitum.
In other words, increasing body weight is a by-product of advances in wealth and income, producing healthier, i.e. larger children, who, in turn, produce better nourished, i.e., larger, children.
The “techno” part of this evolution include everything from American colonists moving from a wooden plow to an iron one; improvements in food production and distribution, refrigeration, canning, changes in water, sanitation and public health which reduced mortality from infectious diseases while improving nutrition for more and more people.
The “physio” part incorporates research on the fetal origins of adult disease and will support the attention to epigenetics as an important aspect in the development of obesity. This is not purely genetics or genetic determinism but the process of transition of improvements in nutrition to the health of the mother and her survival as well as to the survival of more children for longer periods of time. Epigenetic changes is coming into focus as a critical stages for the development of obesity and will certainly receive more attention in the future. Epigenetic changes in early life and future risk o… [Int J Obes (Lond). 2010] – PubMed result
Is there an end to the process or is there a natural limit to this growth? Well, we don’t really know but none appears so far. (It seems to me, at least, that evolution has not felt it necessary to provide unlimited height of the species since there does not appear any survival value to being taller. On the other hand, nature has felt that there was a distinct survival value to being able to store energy (read fat) on our bodies and there does not seem to be a particular limit to this.)
Interestingly, the authors find that, for American white males ages 40-59, the increase in BMI from 1870 to 1980 is less closely related to food consumption than to reduction of contaminated environments and work hours. “Not only have working hours,” they write, “declined substantially throughout the twentieth century, but the type of work became more sedentary, and so required less energy.” However, “The recent large increase of BMI in 1980-2000 (6 percent) is highly connected to increased food intake during the period (22 percent). (At p. 336) Further, they note the average BMI of American white males has increased by 15.7% throughout the 20th Century, half during the last two decades of the twentieth century. “This means that American body size is rapidly moving toward overweight and obesity.This would seem compatible with a new finding from Tim Church and colleagues at the Pennington Biomedical Research Center that in the 1960’s about half of jobs in private industry required at least moderate physical activity. That figure is now less than 20%. Over the last 50 years, occupational daily energy expenditure decreased from by 142 calories in men and a similar amount in women. Trends over 5 Decades in U.S. Occupation-Related P… [PLoS One. 2011] – PubMed result
What are the policy implications of this Technophysio Evolution?
First, increases in body size are a product of 300 years improvement in technology, productivity and standards of living. This evolution began long before television, fast food, vending machines, sugar-sweetened beverages and other would-be villans in the obesity epidemic.
Second, the very same nutritional improvements which led to larger bodies in Europe and the United States are being actively pursued in undernourished parts of developed nations and throughout the developing world. This indicates greater and greater levels of obesity in the developing world with obesity related diseases.
Third, epigenetics needs to receive more attention as a point of intervention in the development of obesity.
Fourth, simplistic views that blame individuals and proclaim that just cutting back food or going to the gym will fix the obesity epidemic. Strategies which just repeat the ELEM mantra (Eat Less Exercise More) have to be questioned if those strategies are likely to affect this profound historical trend.
A few years ago, Gina Kolata, in her book, Rethinking Thin (Farrar,Straus and Giroux, 2007) discussed the views of some obesity researchers that we are looking at a new stage in the evolution of the species. This tome adds significant evidence that our obesity strategies need to be re-thought to take this 300 year trend into account.