Saturday, May 28, 2011

Crushing obesity

In the early 1990s, half of the U.S. population could proudly state that they were neither overweight nor obese. Today only one third can make that claim. The rate of obesity* has nearly doubled from about 15 percent of the population to more than 26 percent in less than two decades.

But numbers alone seem inadequate to describing the magnitude of the problem. The U.S. Centers for Disease Control and Prevention (CDC) put together a series of maps showing obesity rates from 1985-present.

Obesity's rapid spread across America:
In the maps below the lightest blue represents obesity rates by state of less than 10 percent. The darkest red-orange represents obesity rates of 30 percent or higher. Note the rapid shift over 20 years from no states having reported obesity rates above 15 percent (in 1989) to no states having rates below 15 percent (in 2009).

So why are we getting fat?
There are a variety of factors at play in the rising obesity epidemic. An article in Slate this week, and on my blog last summer, describes the link between obesity and commuting. The Federal Reserve and the USDA suggest that increased food consumption, particularly fast food, is the primary driver expanding America's waistlines.

New research, from Pennington Biomedical Research Center at Louisiana State University, digs into another trend - our economy - to understand the obesity epidemic. Using data on occupational patterns since the 1960s, coupled with weight data, and energy expenditure (i.e. calories burned) per day per occupation, they come to a startling conclusion: modern jobs make us fat. Specifically "In the early 1960's almost half the jobs in private industry in the U.S. required at least moderate intensity physical activity whereas now less than 20% demand this level of energy expenditure. Since 1960 the estimated mean daily energy expenditure due to work related physical activity has dropped by more than 100 calories in both women and men."

Research from the Mayo Clinic, American Cancer Society, and have come to a similar conclusion - sedentary behavior leads to obesity. So the advent of desk jobs that require sitting for long periods of time may be a primary cause of rising rates of obesity.

One conclusion is certain, whatever the cause (or, more likely, causes) of obesity, the cost is too high to be ignored. Obesity increases a person's risk of heart disease, diabetes, high blood pressure, and certain types of cancer, among other ailments (source: CDC). In 2006 the increased rate of obesity resulted in an estimated $40 billion in healthcare costs.

*According to the CDC, obesity is “defined as a Body Mass Index (BMI) of 30 or greater.BMI is calculated from a person's weight and height and provides a reasonable indicator of body fatness and weight categories that may lead to health problems. Obesity is a major risk factor for cardiovascular disease, certain types of cancer, and type 2 diabetes.

Map images courtesy of the U.S. Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System.

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