How Does Food Marketing Spread Obesity?
The spread of obesity suggests America’s bulging waistlines may have more to do with food marketing than genetics or individual choice
An international team of researchers, led by City College of New York physicist Hernán Makse, found correlations between the epidemic’s geography and food marketing and distribution patterns. The results are published in the journal Nature.
“We found there is a relationship between the prevalence of obesity and the growth of the supermarket economy,” Professor Makse said. “While we can’t claim causality because we don’t know whether obesity is driven by market forces or vice versa, the obesity epidemic can’t be solved by focus on individual behavior.”
The teams findings, published online this week in “Scientific Reports,” come as a policymakers are starting to address the role of environmental factors in obesity. For example, in New York Mayor Michael Bloomberg wants to limit serving sizes of soda sweetened with sugar to 16 ounces as a way to combat obesity.
The World Health Organization considers obesity a global epidemic similar to cancer or diabetes. It is a non-communicable disease for which no prevention strategy has been able to contain the spread
Because obesity is related to increased calorie intake and physical inactivity, prevention has focused on changing individuals’ behaviors.
However, prevalence of non-communicable diseases
reflects spatial clustering, as does the spread of obesity shown “high susceptibility to social pressure
and global economic drivers."
Professor Makse and his colleagues believe that these earlier findings suggest collective behavior is more significant in the spread of the obesity epidemic than individual behavior, such as genetics and lifestyle choices. To study collective behavior, scientists implemented a statistical cluster analysis based on the physics on the phenomena.
Using data collected at the county-level (provided by the U.S. Centers for Disease Control Behavior Risk Factor Surveillance Systems) for the period of 2004 through 2008, they analyzed spatial patterns.
Over the 2004 through 2008 time span of the epidemic - which has Greene County, Ala. as its epicenter - two clusters have emerged spanning distances of 1,000 kilometers: (1) the Appalachian Mountains, (2) the lower Mississippi River valley.
The map shows obesity prevalence and also points out that neighboring areas tend to have similar percentages of obese populations, i.e. people with a body mass index greater than or equal to 30. Researchers measured the influence of a set of characteristics in one county to another county at a given distance. Characteristics studied included (1) population density, (2) prevalence of adult obesity and (3) diabetes, (4) cancer mortality rates and (5) economic activity.
They concluded the clustering patterns found in obesity were the result of “collective behavior, which may not merely be the consequence of fluctuations in individual habits.”
Professor Makse and his colleagues began to believe obesity might be linked to demographic and economic variables. To test this hypothesis, they compared the characteristics of industries associated with food production and sales (supermarkets, food and beverage stores, restaurants and bars) to other sectors of the economy.
This analysis produced the same unusual results as the obesity survey. Areas with above-average concentrations of food-related businesses had a high-than-normal prevalence of obesity and diabetes.
In future studies, Professor Makse plans to apply physics concepts to measure the spread of cancer and diabetes.
“The basic idea is that if a non-communicable disease is spreading like a virus, then environmental factors have to be at work,” he said. “If only genetics determined obesity, we wouldn’t have seen the correlations.”
Collaborating authors were: Lazaros K. Gallos of the Levich Institute and Department of Physics at City College; Pablo Barttfeld and Mariano Sigman of Integrative Neuroscience Laboratory and Department of Physics at Universidad de Buenos Aires (Argentina) and Shlomo Havlin of the Minerva Center and Department of Physics at Bar-Ilan University (Israel). Professor Makse and Dr. Gallos are supported by a National Science Foundation grant.
Published article: "Collective Behavior in the Spatial Spreading of Obesity"
Lazaros K. Gallos, Pablo Barttfeld, Shlomo Havlin, Mariano Sigman & Hernán A. Makse
Scientific Reports 2, Article number: 454 doi:10.1038/srep00454
Received 02 April 2012 Accepted 09 May 2012 Published 14 June 2012
Original press release: http://www1.ccny.cuny.edu/advancement/news/Environmental-Factors-Spread-Obesity.cfm