Journal Issue: Childhood Obesity Volume 16 Number 1 Spring 2006
The Built Environment and Nutrition
The nutrition environment is widely believed to contribute to the epidemic of childhood and adult obesity in the United States and globally.43 Research on nutrition environments is less advanced than that on physical activity environments, though several studies have examined schools as sources of food and found, for example, that the availability of fruits and vegetables in school lunches is linked with youngsters' overall consumption of fruits and vegetables.44 (See the article in this volume by Mary Story, Karen Kaphingst, and Simone French for more details on nutrition in schools.) Few researchers have explored how other neighborhood environments may affect children's eating patterns, and even fewer have looked into their possible links with childhood obesity. Thus we draw mainly from research on neighborhoods in relation to adults' dietary behaviors. The obesity epidemic makes it essential to improve our understanding of the effect of food environments on children as rapidly as possible.
Several aspects of the broad nutrition environment in the United States and other industrialized countries may help explain the increasing prevalence of childhood obesity. Cost concerns and time pressures often lead parents and their children to rely on convenience foods and fast foods. The increasing popularity of dining out over the past two decades has raised the proportion of nutrients consumed away from home. Because convenience foods and restaurant meals are typically higher in calories and fat and lower in valuable nutrients than meals prepared at home, frequent consumption of such food increases the chances of obesity in children and adolescents as well as in adults.45 A lack of access to and the high cost of fruits, vegetables, and other nutritious foods may keep children from consuming them. Expanding portion sizes also appear to be contributing to the obesity epidemic.46
Parents and school administrators are usually called on to provide more healthful foods to children. Evidence indicates, however, that there is a great deal of support for community- level policies that affect local food environments. In a recent survey in California, 50 percent of respondents rated their neighborhoods as being only fair, poor, or very poor in offering healthful food for children, with residents of large cities most likely to give negative ratings.47 Eighty-seven percent of respondents favored requiring fast-food and chain restaurants to post nutritional information, and 46 percent favored limiting the number of fast-food restaurants in a community.48 Respondents generally favored a community approach to reducing childhood obesity rather than leaving it to individual children and families. They rated parents, health care providers, and schools as more important than churches and faith-based organizations in helping to reduce childhood obesity, although relatively more African Americans and Latinos favored a major church role.49
Is the consumers' perception that childhood obesity can be altered through changes in the nutrition environment supported by evidence? Though the literature to date is limited, diverse studies support the principle that nutrition environments may be important influences on eating behavior and may help explain disparities in behavior and disease. The available research on nutrition environments outside schools and homes is based on concepts and empirical data from the fields of public health, health psychology, consumer psychology, and urban planning. It falls generally under two headings: community nutrition environments, which include the number, type, and location of food outlets, and consumer nutrition environments, which cover the availability and cost of, as well as information about, healthful and less healthful foods inside those food outlets. The distinction is important because each could have broad effects on child health, and the opportunities for modifying each can be quite different.
Community Nutrition Environments
In the community nutrition environment, stores and restaurants are the most numerous food outlets. Accessibility can include large issues, such as whether and to what extent these outlets are located in certain communities, as well as such smaller issues as whether they have drive-through windows and what their hours of operation are. Other food sources, such as cafeterias in schools, work sites, churches, and health care facilities, are considered “organizational nutrition environments,” although the nonschool sources may be more influential for adults than for children and youth.
The community nutrition environment may explain some of the racial, ethnic, and socioeconomic disparities in nutrition and health, such as the increasing prevalence of overweight in low-income children.50 Supermarkets, for example, are less common in lower-income and minority neighborhoods than in other neighborhoods.51 And recent evidence links access to supermarkets with such indicators of healthful eating as fruit and vegetable intake among African American adults, household fruit consumption, and a diet quality index for pregnancy.52
Evidence related to restaurants is intriguing but less consistent than that related to stores. A study in New Orleans found higher fast-food restaurant density in minority and lower-income neighborhoods, and a study in Australia found that people living in poorer areas had twice the exposure to these restaurants.53 A state-level analysis in the United States found only a modest link between obesity and the prevalence of fast-food restaurants: the density of such restaurants accounted for only 6 percent of the variance in state obesity rates out of a total of 70 percent explained by a model that included many variables.54 In another Australian study, the availability of take-away food and restaurants was not linked with obesity.55 And in one of the only studies known to explore community nutrition environments and children, overweight was not linked with proximity to fast-food restaurants among urban low-income preschoolers.56
Consumer Nutrition Environments
Data on consumer nutrition environments, by contrast, reflect what consumers encounter within and around a store or restaurant, including the availability of healthful choices, price, promotions, placement, and nutritional information. Price is an influential feature of the nutrition environment. A study of why Americans eat what they do found that cost was the second most important factor, behind taste; convenience was ranked fourth, just after nutrition.57
The availability of healthful foods is also important. Some healthful foods, such as low-fat dairy products and fruits and vegetables, are less available and of poorer quality in minority and lower-income areas. Three studies have documented that disadvantaged neighborhoods have a proportionally lower availability of healthful options and produce of poorer quality than do more affluent and white neighborhoods.58 A study in Los Angeles compared healthful food options and food preparation at restaurants in poorer neighborhoods and at restaurants in higher-income neighborhoods and found fewer healthful menu selections in the lower-income areas.59 A recent study compared the availability and cost of a standard “market basket” of foods from the U.S. Department of Agriculture's Thrifty Food Plan for low-income consumers with a market basket of healthier foods, such as whole wheat bread and lean ground beef. Most low-income consumers had access to the healthier substitutes but at significantly greater cost than the less healthful options.60
Few studies have examined the connection between consumer nutrition environments and eating behaviors. Allen Cheadle and several colleagues found positive links between the availability of healthful (low-fat and high-fiber) products at the grocery store and individuals' consumption of these foods.61 Follow- up surveys two years later, however, found that changes in food availability made relatively little difference to individuals' food consumption over time.62 Researchers must develop better measures to use grocery store surveys to track community-level dietary changes over time.
Indeed, to better understand in general how the nutrition environment affects eating behavior, analysts must continue to improve their measures of how consumer nutrition environments vary. In a food availability study completed in 1990, Cheadle and his colleagues included calculations of the percentage of shelf space used for healthful food options, such as low-fat milk and cheese and lean meats, but such measures may be difficult to apply in contemporary grocery stores, which are now larger and more varied in layout than stores were only a decade ago.63 Other opportunities for consumer measures in stores include assessing product promotion and placement related to children, such as displaying energy-dense foods and placing unhealthful products on lower shelves. The complexity of the research area is clear, but given the public health imperative to improve eating behaviors, it must be a high priority to enhance the public's understanding of the food environments' impact on their eating habits.
An important omission in these studies is that none makes it possible to evaluate the relative contribution of environmental and demographic, psychological, and social factors to diet and obesity. Such multilevel studies are critically necessary to better inform policymakers, researchers, and communities about the potential of environmental change strategies to make a genuine difference in the childhood obesity problem.
Strategies for Change
Although researchers are well informed about which eating patterns will help avoid or reduce obesity, they as yet know relatively little about how environmental change can affect eating patterns. Nevertheless, we can suggest promising strategies, many of which have already been shown to be feasible. Some of these strategies come from recent online and newspaper reports; although they are innovative, they have usually not been carefully evaluated. Others come from previously reported efforts to promote healthful eating, such as reducing fat intake or eating more fruits and vegetables. They provide interesting case examples, though, again, most have not been rigorously evaluated.64
At the community nutrition level, increasing the number of supermarkets (and the variety of fresh produce they sell) in low-income and minority neighborhoods could lead to healthier eating behaviors. Several cities have shown that it is feasible to increase the presence of supermarkets in disadvantaged areas through community advocacy and political action.65 Providing transportation to food sources for poor families who do not own cars appears to be both feasible and popular with shoppers. Locating farmers' markets in low-income neighborhoods has also been well received, although whether the markets affect children's fruit and vegetable consumption or energy balance remains unclear.66
The Urban Nutrition Initiative in West Philadelphia combines the physical activity of gardening with the promotion of healthy eating. This university-community partnership has been recognized as a model health-promotion effort.67 Similar grassroots efforts under the umbrella of community-supported agriculture connect local farmers and consumers to increase the production and consumption of fresh produce.68
Zoning and tax policies can also improve the types and quality of food sold at neighborhood stores. Some restaurant chains, including fast-food restaurants, are increasing their menu of healthful foods by offering side orders of salad or vegetables as part of “combo meals.”69 A Produce for Better Health Foundation study is exploring opportunities to implement healthful menu changes in fast-food and fast-casual restaurant chains and family style restaurants.
Several metropolitan areas have convened forums to brainstorm ways to address their regional childhood obesity problems, with changes to the built environment among the options. Chicago leaders have come together in the Consortium to Lower Obesity in Chicago Children to identify local solutions with special attention to low-income communities and “urban re-design.”70 California health care organizations are promoting more healthful food environments in workplaces, hospitals, and clinics in models that might be adopted regionwide.71 And in San Diego County, a community forum is planning to combat childhood obesity by, among other things, promoting better food labeling and by creating partnerships between the school system and farmers' markets.72