Bulging waistlines may have more to do with collective behaviour than genetics or individual choices, according to a new study.
The research team, led by City College of New York physicist Hernan Makse, found correlations between the epidemic's geography and food marketing and distribution patterns.
"We found there is a relationship between the prevalence of obesity and the growth of the supermarket economy," Makse, a professor, 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 behaviour," the journal Scientific Reports said.
The teams findings 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, said a university statement.
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' behaviours. However, prevalence of non-communicable diseases shows spatial clustering, and the spread of obesity has shown "high susceptibility to social pressure and global economic drivers."
Makse and his colleagues hypothesized that these earlier findings suggest collective behaviour plays a more significant role in the spread of the epidemic than individual factors such as genetics and lifestyle choices.