TUESDAY, June 19 (HealthDay News) -- People who shop at lower-cost supermarkets are more likely to be obese than those who shop at higher-priced stores, according to a new study.

The findings suggest that supermarket prices -- rather than proximity -- may be a key weapon in the United States' fight against obesity.

Using the Seattle Obesity Study and information collected from a 25-minute phone survey, researchers from the University of Washington in Seattle examined information on a group of residents in King County, Wash.

Specifically, the researchers analyzed where the residents primarily shopped for groceries and what brands of food they bought. They also divided the supermarkets used by the residents into three price levels based on the average price of 100 products.

After taking into account the shoppers' demographics, education and income, the researchers found that only one in seven participants said they shopped at the nearest supermarket. The researchers pointed out proximity may be less important in King County than in urban areas, since residents there typically drive to the supermarket.

The study, published June 14 in the American Journal of Public Health, also found obesity rates were linked to the type of supermarket the people used. The prevalence of obesity was just 9 percent among those who shopped at higher-priced supermarkets, compared to 27 percent at lower-cost stores.

Although bringing supermarkets closer to underserved areas may help combat the obesity epidemic, the researchers said making healthy foods more affordable is a key strategy that also should be considered.

"Systematic efforts to reduce obesity will need to take economic inequalities into account," the study's authors wrote in a news release from the American Public Health Association. "Ensuring equitable access to healthy, affordable foods -- with the emphasis on affordable -- may be key."

More information

The U.S. National Institutes of Health provides more information on obesity.