The percentage of food shoppers who are obese is almost 10 times higher at low-cost grocery stores compared with upscale markets, a small new study shows.
Researchers say the striking findings underscore poverty as a key factor in America’s growing girth.
In the Seattle area, a region with an average obesity rate of about 20 percent, only about 4 percent of shoppers who filled their carts at Whole Foods Market stores were obese, compared with nearly 40 percent of shoppers at lower-priced Albertsons stores.
That’s likely because people willing to pay $6 for a pound of radicchio are more able to afford healthy diets than people stocking up on $1.88 packs of pizza rolls to feed their kids, the study’s lead author suggested.
“If people wanted a diet to be cheap, they went to one supermarket,” said Adam Drewnowski, a University of Washington epidemiology professor who studies obesity and social class. “If they wanted their diet to be healthy, they went to another supermarket and spent more."
The findings held true for the three highest-priced grocery stores in the Seattle region, including Whole Foods, where an average market basket of food cost between $370 and $420, and obesity rates went no higher than about 12 percent.
By contrast, at the area’s three lowest-priced stores, including Albertsons, the same basket of food cost between $225 and $280, and obesity rates went no lower than about 22 percent.
“Deep down, obesity is really an economic issue,” Drewnowski said.
His research team studied 2,001 shoppers in the Seattle area between December 2008 and March 2009, tracking their choice of supermarkets and comparing it with their education, income and obesity rates. They measured obesity by asking consumers to report their height and weight, then calculating body mass index. People with a BMI higher than 30 were identified as obese.
Drewnowski was quick to note that the study focused only on Seattle, which has an obesity rate much lower than the U.S. average of about 34 percent. He doesn’t claim that the same rates would bear out in other cities.
Wealthy shoppers usually thinner
But, he said, it’s likely that similar patterns might be found elsewhere: Wealthier people who shopped at higher-end stores would be thinner, while poorer people who shopped at cheaper stores would be fatter.
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It’s not a matter of availability, Drewnowski said. All of the stores in his study stocked a wide range of nutritious food, including plenty of fruits and vegetables.
Instead, he contends it’s because healthy, low-calorie foods cost more money and take more effort to prepare than processed, high-calorie foods. In a separate study two years ago, Drewnowski estimated that a calorie-dense diet cost $3.52 a day compared with $36.32 a day for a low-calorie diet.
“If you have $3 to feed yourself, your choices gravitate toward foods which give you the most calories per dollar,” he has said.
And the shoppers Drewnowski polled went out of their way to choose stores largely based on price or quality. Only about 15 percent of consumers regularly patronized the stores closest to their homes.
Whole Foods officials said they knew their shoppers were healthy, but that the low 4 percent obesity rate was surprising. Libba Letton, a spokeswoman, said the study confirmed their stores’ commitment to helping people achieve diets that support optimum health.
Albertsons officials declined to comment directly on the reported obesity rates at their stores, instead noting in a statement that they promote healthy choices, particularly through their “better-for-you food finder,” a program that tags shelves to identify foods that meet certain dietary needs.
Access to good foods isn't everything
Drewnowski’s study was paid for by a three-year, $1.2 million grant from the National Institutes of Health. It raises sharp questions about an upcoming government effort, called the Healthy Food Financing Initiative, to spend $400 million starting next year to bring supermarkets to low-income areas. Some researchers have suggested that simply making nutritious foods available in so-called “food deserts” is the key.
But Drewnowski’s findings show that it might not be so simple, said Gary D. Foster, director of the Center for Obesity Research and Education at the Temple University School of Medicine in Philadelphia.
“We can’t assume that access is sufficient,” Foster said. “Access alone probably won’t do it.”
The wide disparity in obesity rates at different stores may be striking, but it isn’t surprising, said Nancy E. Adler, director of the University of California at San Francisco Center for Obesity Assessment, Study and Treatment.
“The Albertsons rate is more the population norm,” she said. “The 4 percent is more outside the range.”
Still, the first-ever study of shoppers and the stores they choose is a stark illustration of an obesity divide fueled by poverty, Foster noted.
“What it says is your social economic status is clearly associated with how overweight you are,” he said.
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