Studies question the pairing of food deserts and obesity
April 23, 2012
April 23, 2012, The New York Times
By Gina Kolata
It has become an article of faith among some policy makers and advocates, including Michelle Obama, that poor urban neighborhoods are food deserts, bereft of fresh fruits and vegetables.
But two new studies have found something unexpected. Such neighborhoods not only have more fast food restaurants and convenience stores than more affluent ones, but more grocery stores, supermarkets, and full-service restaurants, too. And there is no relationship between the type of food being sold in a neighborhood and obesity among its children and adolescents.
Within a couple of miles of almost any urban neighborhood, “you can get basically any type of food,” said Roland Sturm of the RAND Corporation, lead author of one of the studies. “Maybe we should call it a food swamp rather than a desert,” he said.
Some experts say these new findings raise questions about the effectiveness of efforts to combat the obesity epidemic simply by improving access to healthy foods. Despite campaigns to get Americans to exercise more and eat healthier foods, obesity rates have not budged over the past decade, according to recently released federal data.
“It is always easy to advocate for more grocery stores,” said Kelly D. Brownell, director of Yale University’s Rudd Center for Food Policy and Obesity, who was not involved in the studies. “But if you are looking for what you hope will change obesity, healthy food access is probably just wishful thinking.”
Advocates have long called for more supermarkets in poor neighborhoods and questioned the quality of the food that is available. And Mrs. Obama has made elimination of food deserts an element of her broader campaign against childhood obesity, Let’s Move!, winning praise from Democrats and even some Republicans, and denunciations from conservative commentators and bloggers who have cited it as yet another example of the nanny state.
Speaking in October 2011 on the South Side of Chicago, she said that in too many neighborhoods “if people want to buy a head of lettuce or salad or some fruit for their kid’s lunch, they have to take two or three buses, maybe pay for a taxicab, in order to do it.”
Mrs. Obama has also advocated getting schools to serve healthier lunches and communities to build more playgrounds.
Her office referred questions about the food deserts issue to the Department of Agriculture. A spokesman there, Justin DeJong, said by e-mail that fighting obesity requires “a comprehensive response.” The federal effort, he added, includes not just improving access to healthy foods but also improving food in schools, increasing physical education time, and educating people on the importance of healthy diets.
Some researchers and advocates say that further investigation is still needed on whether grocery stores and chain supermarkets in poor neighborhoods are selling produce that is too costly and of poor quality. “Not all grocery stores are equal,” said John Weidman, deputy executive director of the Food Trust, an advocacy group in Philadelphia.
It was difficult to design a study that could rigorously answer the questions: Do poor urban neighborhoods lack places to buy fresh produce and is that contributing to obesity? But Helen Lee of the Public Policy Institute of California, a nonprofit, nonpartisan research organization, found a way. For data on where children lived and went to school and how much they weighed, she used a federal study of 8,000 children. For data on the location of food establishments, she used a data set that compiled all the businesses in the nation and included their sizes and locations.
“I knew where the children lived, so let’s take the middle of that neighborhood,” Dr. Lee said. “What is the nearest grocery store? What is the nearest convenience store?”
She used census tracts to define neighborhoods because they tend to have economically homogeneous populations. Poor neighborhoods, Dr. Lee found, had nearly twice as many fast food restaurants and convenience stores as wealthier ones, and they had more than three times as many corner stores per square mile. But they also had nearly twice as many supermarkets and large-scale grocers per square mile.
Her study, financed by the institute, was published in the March issue of Social Science and Medicine.
Dr. Sturm’s study, published in February in the American Journal of Preventive Medicine, had a different design. With financing from the National Institutes of Health, he used data on the self-reported heights, weights, and diets of more than 13,000 California children and teenagers in the California Health Interview Survey. The survey included the students’ addresses and the addresses of their schools. He used a different data set to see what food outlets were nearby. Dr. Sturm found no relationship between what type of food students said they ate, what they weighed, and the type of food within a mile and a half of their homes.
He has also completed a national study of middle school students, with the same result — no consistent relationship between what the students ate and the type of food nearby. Living close to supermarkets or grocers did not make students thin and living close to fast food outlets did not make them fat. The study will be published soon in Public Health.
It is unclear how the idea took hold that poor urban neighborhoods were food deserts but it had immediate appeal. There is even an Agriculture Department “food desert locator” and a “National Food Desert Awareness Month” supported by the National Center for Public Research, a charitable foundation.
But, Dr. Lee said, studies lending support to the idea tended to be limited by methodological difficulties.
For example, some researchers looked at neighborhood food outlets but did not have data on how fat residents were. Others examined small areas, like part of a single city and extrapolated to the entire nation. Others had a different problem. They looked at much bigger areas like ZIP codes, which include people of diverse incomes, making it hard to know what happened in pockets of poverty within those regions.
Some researchers counted only fast food restaurants and large supermarkets, missing small grocers who sold produce. Some tallied food outlets per 1,000 residents, which made densely populated urban areas appear to have fewer places per person to buy food. A more meaningful measure, Dr. Lee said, is the distance to the nearest stores.
In one neighborhood in Camden, N.J., where 80 percent of children are eligible for a free school lunch, children bought empanadas, sodas and candy at a grocer, while adults said they had no trouble finding produce. Wedged in among fast food restaurants, convenience stores, sit-down restaurants, take-out Chinese and pizza parlors were three places with abundant produce: Pathmark and Save-A-Lot supermarkets and a produce stand.
What do you think about these research studies? Do you think increasing access to healthy foods will help curb childhood obesity?