But the correlation between weight and shopping preferences was found to extend beyond an individual's own behavior.

Other social considerations -- namely, the shopping habits of neighbors -- were also an important factor. For example, a 5-foot-5-inch person who lived in a poor neighborhood whose neighbors shopped in a wealthier area would weigh an average 9.2 pounds less than if he or she lived in a poor neighborhood whose residents shopped in a poorer area, the researchers concluded.

Where people live may influence their food choices as much or more than where they themselves shop, said study lead author Sanae Inagami, MD, a researcher with the Rand Corporation in Los Angeles.

"My feeling is that your neighbors do influence your health," Inagami said. "Who you know and where you go shopping is related to your level of obesity."

Limited Selection of Healthy Foods

For years, researchers have been trying to document a connection between obesity among the poor and the limited selection of healthy foods in their local grocery stores.

Inagami and her colleagues examined census figures from 2000 and linked them to 2,144 Los Angeles County residents who were surveyed about their eating and health habits from 2000 to 2002. Their findings indicate the relationship might be even more complicated than previously thought.

"I don't think we're going to be making any impact on obesity without looking at how social factors play a role," Inagami said.

Poor People Used to Be Thinner

Thomas Farley, MD, chair of the Department of Community Health Sciences at Tulane University, said that while the study adds to existing knowledge about the link between obesity and poor neighborhoods, it doesn