American society has become “obesogenic” according to the US Centers for Disease Control and Prevention (CDC): their latest report shows that nine states now report more than 30 per cent of adults are obese, yet it was only ten years ago that no state had a 30 per cent or more rate of obesity in its adult population.

The nine states that surpass the 30 per cent obesity rate were found to be: Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee, and West Virginia.

On its Obesity webpage, the CDC describes American society as “obesogenic”, where people live in environments that promote over-eating, unhealthy food, and physical inactivity.

The latest evidence appears to reinforce this: in just one year, since 2009, the number of states with an obesity prevalence of 30 per cent or more has tripled to nine, according to the CDC’s second MMWR “Vital Signs” report, released on Tuesday.

Moreover, not one state has met the Healthy People 2010 national goal of 15 per cent adult obesity prevalence, and only two, the state of Colorado and the District of Columbia report an obesity prevalence under 20 per cent (18. and 19.7 per cent respectively).

CDC Director Dr Thomas Frieden told the press that obesity is still a major public health concern in the US, and if we don’t continue to address this with intensive and comprehensive efforts, we will see more and more people getting sick and dying from obesity-related causes “such as heart disease, stroke, type 2 diabetes and certain types of cancer, some of the leading causes of death”.

The CDC report shows that based on self-report data, an additional 2.4 million adult Americans (aged 18 and over) entered the obese category between 2007 and 2009, representing a rise of 1.1 per cent.

Obesity-related medical costs are also high, says the report, estimating the total cost in 2008 at 147 billion US dollars, with obese people costing an extra 1,429 dollars each to treat compared to people of normal weight.

The report bases its findings on new figures from the Behavioral Risk Factor Surveillance System (BRFSS). This system yields state-level public health data and gives states a way to monitor their progress toward the national Healthy People goals.

The system gets it data from telephone surveys: about 400,000 people are surveyed for the obesity data. They are asked to give their height and weight over the phone. From this the survey calculates their BMI (Body Mass Index, the weight in kilos divided by the square of the height in metres).

A BMI of 30 and over counts as obese: and this would include for instance a woman 5 foot 4 inches tall (1.63 m) weighing 174 pounds (79 kilos) or more, or a man 5 ft 10 ins tall (1.78 m) weighing 209 pounds or more (95 kilos).

But the CDC reckons that the BRFSS obesity estimates are under-representative: true obesity prevalence is higher than their figures suggest because research shows that in telephone surveys, men and women often say they are taller and weigh less than they really do.

Dr William Dietz, director of CDC’s Division of Nutrition, Physical Activity and Obesity, says that is why estimates based on the the BRFSS data suggest an overall national level of 26.7 per cent, which is 7.2 lower than the 2007-2008 estimate of 33.9 per cent (nearly 73 million Americans) that is based on NHANES (National Health and Nutrition Examination Survey) data, where people’s height and weight are actually measured rather than self-reported.

Using the BRFSS data CDC researchers also reported how obesity rates vary among different parts of the American population, for example:

  • Non-Hispanic blacks had the highest overall obesity rate at 36.8 per cent.
  • Among non-Hispanic black women, the obesity rate was even higher at 41.9 per cent.
  • Among Hispanics the obesity rate was 30.7 per cent.
  • Among non-high school graduates the rate was 32.9 per cent.
  • The Southern states had an obesity prevalence of 28.4 per cent.
  • In the Midwest, the obesity rate was 28.2 per cent.

Dietz said that obesity is a complex issue that requires action at both the personal and the community level.

“People in all communities should be able to make healthy choices, but in order to make those choices there must be healthy choices to make,” he said, explaining that to address the issue we have to change communities so that people are surrounded by environments where the easiest path is to eat healthy food and be active.

The CDC also refers to two recent reports: The Surgeon General’s Vision for a Healthy and Fit Nation 2010, and the 2010 report from the White House Task Force on Childhood Obesity, both of which highlight a cluster of three actions to tackle the obesity crisis, with a need to address:

  1. Both diet and exercise,
  2. Work across multiple settings (eg medical, workplace, community) and multiple sectors (eg industry and government), and
  3. Change individual behaviors in tandem with the environments and policies that influence them.

In support of this last point, there is evidence from research that encouraging physical activity (for example through increased access and improved community design), and healthy eating (eg improved access to supermarkets offering healthy foods, fruits and vegetables), are linked to real increases in physical activity and dietary improvements.

Correction: this article amended 22.00 PDT to add the paragraph listing the nine states that surpass the 30 per cent obesity rate, apologies to our readers, this was inadvertently missed out in the first issue.

“State-Specific Obesity Prevalence Among Adults – United States, 2009.”
CDC: Morbidity and Mortality Weekly Report (MMWR), August 3, 2010 / 59 (Early Release); 1-5.

Source: CDC.

Correction: this article amended 22.00 PDT to add the paragraph listing the nine states that surpass the 30 per cent obesity rate, apologies to our readers, this was inadvertently missed out in the first issue.

Written by: Catharine Paddock, PhD