America's Obesity Epidemic Hits the Poor the Hardest

More than two in every three American adults are considered overweight or obese, according to data from the National Health and Nutrition Examination Survey.

And new research from the University of Arkansas (UA) suggests that obesity does not affect all parts of the country equally. It is instead concentrated in areas affected by what researchers described as an "ecology of disadvantage."

In order to study patterns of obesity across the nation, the team combined data from the U.S. Census and the 2015 Behavioral Risk Factor Surveillance System, which includes information on chronic disease rates from the 500 largest American cities. The findings are published in the journal Obesity Research & Clinical Practices.

"Our results indicate a clear connection between obesity prevalence, income inequality, and the racial and ethnic population composition across census tracts in the 500 largest U.S. cities," the authors wrote in the study.

Census tracts are small, relatively stable geographic areas that tend to have a population between 2,500 and 8,000 people (although they can range from anywhere between 50 to 28,000 people). Obesity studies generally overlook these areas in favor of focusing on regional, state or county patterns.

"What this data provided was the ability to map chronic disease as it relates to where people live," Kevin Fitzpatrick, a sociologist at UA said in a statement. "These two big data groups—chronic health disease data and structural place data—have not been combined in this way at this level until now."

The researchers found a strong link between obesity levels and sociodemographic factors such as race, income inequality, education level, age and house value. Places with higher concentrations of low-income, minority populations had increased rates of obesity.

"As the gap between rich and poor increases, so does this growing disadvantage of health and well-being for low-income, predominately minority populations," the report states.

According to their results the highest levels of obesity were found in southern coastal areas of Texas, Alabama, Louisiana, New Jersey, Massachusetts, eastern coastal regions of New York and the Great Lakes region around Michigan, Illinois and Wisconsin. Meanwhile, cities in southern California had the highest number of people considered to have a normal weight.

Clearly "place matters," when determining someone's chances of having obesity in America, according to Fitzpatrick.

"'What's your zip code?' is fast becoming one of the most important things your doctor could ask you, not 'How are you feeling today?'"