The latest data from the Centers for Disease Control and Prevention affirms an alarming trend: we’re fat and not getting any slimmer. An estimated 35 percent of U.S. adults are obese, and another third still maintain weights exceeding those deemed healthy. This doesn’t bode well for governments and individuals paying insurance premiums, especially with the country’s aging population.

But there are antidotes to the problem, and among the best could be sidewalks and bike lanes. The infrastructure not only facilitates outdoor recreation and an alternative to congested roadways, but data shows it delivers slimmer waistlines in some of the nation’s largest metropolitan regions.

A Governing review of census and CDC data finds communities where more residents walk or bike to work boast significantly healthier weights. The analysis of 2010 statistics for 126 metropolitan areas finds these communities are strongly correlated with higher numbers of residents who are neither obese nor overweight.

Historically, studies have linked trails, sidewalks and bike lanes with an increase in walking or cycling. As medical costs continue to rise and evidence mounts that such infrastructure also improves well-being, more officials might look to give health consideration greater standing in transportation planning.

“The more access that people have to these kinds of places, the more likely they are to be healthy,” said Susan Polan, associate executive director for public affairs and advocacy with the American Public Health Association.

Metropolitan regions with the healthiest weights are home to high counts of walkers and bike commuters.

The CDC considers those with sizable weights for their height (body mass index of 30 or greater) to be obese, and others who are not quite obese, but exceeding healthy weights, to be “overweight.”

Approximately half of Fort Collins-Loveland, Colo., metro area residents are neither overweight nor obese. That might not sound like a lot, but it’s the highest percentage of healthy residents of all metro areas surveyed for the CDC’s 2010 Behavioral Risk Factor Surveillance System, an annual telephone survey measuring a range of health issues. Accordingly, census figures indicate 5.3 percent of Fort Collins-Loveland area commuters walk or bike as their primary form of transportation to work, one of the highest rates in the country.

Five of the top 10 healthiest metro areas in terms of weight were among the 10 regions with highest percentages of residents walking or biking to work in the Governing analysis. Although tallies of walkers and bikers are small compared to all commuters, many who walk or bike to public transit stations aren’t counted in the Census Bureau’s American Community Survey data, and significantly more exercise outdoors outside of their daily commutes.

While only a fraction of workers in an area may opt to bike or walk to work, having the necessary infrastructure in place compels others to use it more regularly.

Spending hours a day in a car or living a sedentary lifestyle makes it difficult to shed pounds. Exercising helps, and eating habits, medical conditions and other factors understandably drive obesity rates as well.

Along with commuting habits, other measures showed statistically significant relationships with healthy weights in the analysis. Healthier metro areas were most closely correlated with the portion of a region’s population holding at least a bachelor’s degree. The Bridgeport-Stamford-Norwalk, Conn. metro area, a wealthy region ranking near the top in education attainment, recorded the lowest obesity rate in the CDC’s 2010 survey.

Still, the correlation between commuting and residents not considered obese nor overweight was strong–16 percent greater than the relationship with median household income.  An area’s average commute time was slightly correlated with weight, but was not statistically significant.
Scatter plot of metro areas’ walkers/bike commuters correlated with healthy weights:

The CDC recommends a range of infrastructure for communities to rein in obesity. Bike lanes, shared-use paths and bike racks promote cycling. Urban design with adequate sidewalks, lighting, street crossings and similar features supports walking and other physical activity. The agency also suggests localities work to cut miles driven on roadways.

American Public Health Association’s Polan cited public transit projects and converting old rail lines into trails as two of the more popular initiatives localities pursue. It’s particularly important, she said, to encourage kids to walk to school and educate them about pedestrian safety at a young age.

Last year, Los Angeles County, Calif., earmarked nearly $16 million in funding for an initiative aimed at curbing obesity, part of which included expanding bike networks and promoting open spaces.

“There are a lot of smaller initiatives that can engage and energize people and make them realize what a difference they can make at the local level,” Polan said.

When cutting expenses, health costs are an easy target. A recent study by two Lehigh University researchers reported obesity-related costs accounted for $190 billion annually in U.S. health expenditures, nearly 21 percent of the country’s total bill.

Advocates often push for related projects in transportation planning, but the amount of weight officials actually give to health concerns varies. While it may be a major consideration in some communities, others focus strictly on economic concerns, Polan said.

John Norquist, president of the Congress for the New Urbanism, said many American cities have taken steps in recent years to promote walking and biking.

To improve walkability, connected street grids – with slower speed limits and no more than two lanes in each direction – are a key component, he said.

Those looking to move can use the popular walkscore.com website to measure how accessible an apartment or home’s various neighborhood amenities are on foot. Norquist, whose group advocates mixed-use and transit-oriented development, cited New York City, San Francisco, Denver and Albuquerque, N.M., as cities making strides in developing walkable communities.

Biking has also accelerated, Norquist said, particularly in Seattle and other older urban environments. “The old downtowns are in great shape for biking,” he said.

Young people’s attitudes toward biking and public transit have shifted, with more seeking alternatives to long car rides, Norquist said. Bicycle manufacturers have joined in the push to remake communities, hiring lobbyists to pressure Washington and support more bike-friendly transportation planning policies.

The emphasis on healthy lifestyles in urban design isn’t new, though. Richard Jackson, a former head of the CDC’s National Center for Environmental Health who has since become one the movement’s most vocal proponents, published an article linking built environments to adverse health effects back in 2001.

Norquist said that the benefits of walking and biking have now become one of the central themes of urbanists’ arguments for urban revival as recreation represents an increasingly key aspect of living downtown.

“It’s really going to be a big factor, because people want to be healthier,” he said. “It’s a very personal thing.”