It could be your neighborhood that's making you fat — or keeping you slender.

A new study found that the year your neighborhood was built may be just as important as diet and exercise for shedding pounds. Those who live in neighborhoods built before 1950 are trimmer than their counterparts who reside in more modern communities, the study reported.

“The older neighborhoods had a reduced level of obesity because they were generally built with the pedestrian in mind and not cars,” said Ken Smith, a co-author of the study and professor in the department of family and consumer studies at the University of Utah. “This means they have trees, sidewalks and offer a pleasant environment in which to walk.”

In the study, which appears in the September issue of the American Journal of Preventive Medicine, the researchers found that on average men weighed 10 pounds less if they lived in older, more walkable neighborhoods while women weighed about six pounds less.

The older neighborhoods also tend to have a variety of stores and businesses located within walking distance, so people wind up traveling by foot to do errands, go to local restaurants or other activities, Smith added.

Modern neighborhoods, on the other hand, generally consist of large areas with nothing but housing, an arrangement that hinders walking and forces people to drive more to get around. 

Amy Crook, a 34-year-old freelance graphic designer, gained 30 pounds over the course of two years after she moved to a sprawling neighborhood in Bowie, Md., in 2005.  “There was nothing to walk to,” said Crook, who noted that she drove everywhere, even to the grocery store two blocks away because there were no sidewalks.

But after she relocated to a more walkable neighborhood in San Leandro, Calif., she dropped the weight without even trying. She didn’t consciously make an effort to increase her exercise levels or modify her diet, she says, but found herself walking more doing daily errands, such as going to the grocery store or bank.

“There’s a whole neighborhood in the area, including banks, restaurants, grocery stores and bookstores,” Crook said. “It’s all within walking distance and it’s easier to get to them by walking than by driving.”

The older the neighborhood, the lower the weight
In the study, Smith’s team used height and weight data from driver’s licenses to calculate the body mass index (BMI) of nearly 454,000 people, ages 25 to 64, living in Salt Lake County, Utah. They then compared BMIs across neighborhoods that had been scored for their walkability, which included whether the area had a diverse array of shops and businesses, sidewalks and lots of intersections.

The researchers found that older neighborhoods were both more walkable and had lower rates of overweight and obese people. For each decade older the neighborhood was, the risk of obesity dropped by about 8 percent in women and 13 percent in men.

Lawrence Frank, a public health and urban planner researcher at the University of British Columbia in Vancouver, Canada, said the findings fit with previous showings that sprawl is associated with higher rates of obesity and people who spend more time in cars are more likely to be obese.

“The take away message is that we’ve got to start building communities the way we used to,” said Reid Ewing, a research professor at University of Maryland’s national center for smart growth research and education in College Park. “Prior to World War II, we basically built walkable communities, but for last 60 years we’ve been building sprawl and people don’t have to be physically active as part of their daily lives.”

Fighting obesity with architecture
Building more walkable neighborhoods could be one strategy to fight the rising rates of obesity across the country, Smith said. “It’s very difficult to get people to change lifestyles but maybe we can change their environment to promote healthier outcomes,” he said.

In the meantime, people may want to consider the walkability of neighborhoods when they move, Smith said. (The Web site Walk Score rates the walkability of particular addresses.)

People who live in sprawling neighborhoods can still find ways to get in extra activity, such as playing sports, Ewing said. But walking alone isn’t enough to take off the pounds, diet is also important.

For Crook, moving to a more walkable neighborhood helped her both eat healthier and get in more walking. She stocks up on fresh fruits and veggies during her trips to the local farmer’s market, which prompts her to cook more rather than eating out. She’s still losing weight, she says, and has had to replace all her jeans with smaller sizes.

Steve Mitchell is a science and medicine writer in Washington, D.C.  His articles have appeared in a variety of newspapers, magazines and Web sites, including UPI, Reuters Health, The Scientist and WebMD.

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