EUGENE, Ore. (AP) -- A growing chorus of planners, health officials and others has said that spread-out suburbs discourage walking and might encourage obesity.

But two Oregon State University researchers have concluded there is little connection between urban sprawl and the expanding waistlines of Americans.

Professors Andrew Plantinga and Stephanie Bernell say people who are overweight and sedentary tend to gravitate toward neighborhoods with fewer opportunities for walking because it's not something they care about.

"We found very little evidence that it was the physical environment causing obesity," Plantinga said. "Rather, it seemed to be more about how people choose the types of neighborhoods to live in."

The study by Plantinga, a professor of agriculture and resource economics, and Bernell, who works in the OSU department of public health, looked at the relationship between urban sprawl and neighborhood choice based on weight, measured as body mass index or BMI. It was published in the Journal of Regional Science.

The researchers found that fit people choose to live in neighborhoods that allow them to walk to work or shop and fat people pick places where they need a car.

The study was adjusted to eliminate differences due to income and other factors.

Plantinga said the studies don't mean mixed-use development is a bad idea. Reducing sprawl has other benefits, such as reduced traffic and fuel use, he said.

"I think there are lots of really good reasons why you might want to pursue smart growth policies," Plantinga said. "But I think that we have to be careful in thinking that smart growth can deliver health benefits, as people have been suggesting. The public health benefits may in fact be very limited."

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