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Kaid Benfield’s Blog

US obesity rates continue to soar, in part because of automobile dependence

Kaid Benfield

Posted May 9, 2012

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  the unfortunate trend (by: Mike Licht,, creative commons license)

The headline in Tuesday’s USA Today was shocking: “Obesity could affect 42% of Americans by 2030.”  That is nearly triple the rate experienced just three decades ago, according to an article written by Nanci Hellmich.   At current rates, eleven percent of Americans could be “severely obese, roughly 100 or more pounds over a healthy weight."

The findings come from a Duke University study presented at a meeting hosted by the Centers for Disease Control and to be published in the American Journal of Preventive Medicine.

The consequences for our health (and, for that matter, our economy) are quite serious.  Earlier this year I reported data on Type 2 diabetes, for example, which is obesity-related and has been rising at the same rate as body weight in the US for the last few decades.  fat to obese (by: FBallon, creative commons license)Diabetes is the leading cause of nontraumatic amputations, eye disease, and kidney disease, and is a major factor in the development of cardiovascular disease. Cardiovascular disease is the number one cause of death in diabetes patients.

My fear is that we pay insufficient attention to this disturbing trend because, like global warming, it has become more pronounced gradually and tends not to have sudden and dramatic consequences.  We get used to it.  But, unlike global warming, the environmental factors associated with the rise in obesity have not attracted the attention of the environmental community to any great degree.

As Dick Jackson -- one of the country’s top environmental health experts -- has been telling us for years, this needs to change.  There are all sorts of causes of the obesity epidemic, including of course poor nutrition.  But the downturn in physical activity because of the way we have designed our cities and suburbs -- for driving more than walking -- is also a significant factor.  There are studies showing that transit use is associated with reduced body weight, as is is the presence of shops and services within walking distance of the home.

  Plano, TX (by: Justin Cozart, creative commons license)

And now there’s more.  Nate Berg, writing for The Atlantic Cities, reported yesterday that a new study of automobile commuters has found that, the longer the commute, the more likely one is to have reduced fitness, increased weight, high cholesterol, and elevated blood pressure:

“The activity of driving to work should be better thought of as inactivity, and all that time sitting on your butt is slowly eating away at your cardiovascular health – and probably adding to your waistline. Those who have farther to travel tend to see worse results according to the study, which will be published in the June issue of American Journal of Preventive Medicine.

“The study tracked 4,297 people who lived and worked in 11 counties in the Dallas-Fort Worth or Austin, Texas, metropolitan areas, and compared their commuting distances with various medical health indicators, including cardiorespiratory fitness, body mass index, and metabolic risk variables like waist circumference. light rail transit, Phoenix (by: Ixnayonthetimmay, creative commons license)The longer the commute, the greater the likelihood these health indicators measure up on the fat and sick side of the scale. The researchers also found that people who drove longer distances reported doing less physical activity overall.”

Berg reports further that these associations were found even when the researchers controlled for individual characteristics such as personal physical activity habits and level of fitness.

Obesity, heart disease and diabetes are health problems, to be sure.  But they are environmental problems as well.  We know how to locate and design our communities so that we don’t need to drive so much and have more opportunities for walking in our daily routines.  The basic principles of smart growth point us in the right direction.  What we need to understand better is that following these principles -- which, incidentally, the market supports -- is important not just to reduce emissions and conserve land.  It can also save lives.

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Kaid Benfield writes (almost) daily about community, development, and the environment.  For more posts, see his blog's home page.  Please also visit NRDC’s sustainable communities video channel.

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BSMay 9 2012 10:08 AM

Good article.

What about people who take public transit long distances? It would seem that it's the time spent commuting that reduces time available for physical activity, regardless whether the commuter is in a car or on public transit.

If that's the case, the issue wouldn't so much be what method of transportation a person utilizes, but rather how far they are from work.

I know a lot of people live far from where they work because housing prices are cheaper. However, I think that they often do not take into account the true cost of commuting (monetary, stress, risk of getting into an accident, lost time) which can often make the suburban location more expensive, not less.

Even when it comes to the cost to drive a car, people routinely only figure the cost of gasoline when in reality gas may only be about 1/3 of the total cost to drive a car (the cost of the car itself usually being the biggest expense).

It seems that in addition to increased use of mass transit and walking, perhaps people need to be better educated on the true cost of a long commute. In many cases, that cost far exceeds what they save by buying/renting a home in the suburbs.

RichardMay 9 2012 01:32 PM

Public transit systems contribute to weight loss and improved health

BSMay 9 2012 01:53 PM

Did those study's differentiate between someone who uses mass transit solely for a long commute to work from a suburb (that generally wouldn't have substantial mass transit use within that suburb) and someone who lives in a city and is able to use mass transit for more than just a commute to work?

I can say for certain that my new 1hr commute (on a bus plus walking nearly 1mi/day) has reduced my overall level of physical activity compared to what it was when I lived in a small town and drove 10 minutes to work and back. I would actually have MORE time to exercise if I drove to work (and still walked maybe 0.5mi/day to and from my car) because it would save me 15-30 minutes of transit time depending on the day.

On the other hand, I can certainly see how someone in an urban area with a short commute who uses mass transit regularly (work, shopping, etc) would certainly get more physical activity compare to someone in the same urban area who only drives.

Kaid @ NRDCMay 9 2012 02:44 PM

Fair points. Someone who has time and inclination to exercise for fitness will likely do more exercise if she has more time, regardless of how she gets to work.

The only study on point that I know well is the Charlotte study (linked) that looked at the weight of commuters before and after they started using transit when that city's first light rail line was built. The researchers found that their weight, on average, dropped. This is presumably because they began walking more to, from, and within the transit stations than they had been before using transit.

Kevin MatthewsMay 9 2012 04:17 PM

Great posting. Thanks especially for connecting back to the Ewing and Cervero work on distance-from-downtown - the single most significant planning factor... which we also covered in ArchWeek -

Around here in Oregon, the public health effects of sprawl, and the impact of urban planning factors on daily physical activity, have been part of the core agenda for many years - even among environmental groups. :-)

Meanwhile, however, the counter-lobby from sources like the NAHB and their local affiliates has been relentless.

BSMay 9 2012 07:22 PM

Kaid--Thanks for the reply. It would be interesting indeed to see that study expanded to compare drivers vs those who ride mass transit (although the study may not be able to show a causal relationship since it's also possible that healthy people are more likely to prefer mass transit that requires walking rather than driving).

And for what it's worth, my comments on your other thread were sincere and not intended to harass you. I like your blogs. And I hate being wasteful of any resource. I think the issue I raised really is one that deserves additional attention.

Selma AmaralMay 11 2012 08:55 AM

Can you see the correlation between healh problems & environmental problems? They come together. It is a modern lifestyle dilemma: we are degrading our environment at the same time disgracing our health by burning so much petroleum, producing junk food and, thus, generating so much trash. what really bothers me is that the next generations will be paying high for our mistakes. I really believe, we should be more conscious and aim for a more sustainable life and developement.

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