Obesity is a multifactorial disease that has many contributing factors, including the food environment. Food environments in which energy-dense prepared foods (ready-to-eat foods that can be eaten outside the home or brought back or delivered to the home to eat) are readily available are associated with the increasing prevalence of obesity (1–3). As a consequence, environmental interventions may be more cost-effective, sustainable, and successful at reaching a large population than individual interventions (4). Today, Americans spend about half of their food dollars eating out (5,6) compared with 25% in 1955 (7). Americans are expected to spend $660.5 billion in 2013 on eating out, a 15-fold increase from 1970 (adjusted to current dollars) (7). The total energy intake per capita increased on average by 570 kcal between 1977–78 and 2003–06; this increase has been attributed to greater portion sizes and a greater frequency of eating out (8). Although prepared foods are generally more costly than foods prepared at home, people who have low incomes consume them at high rates (9–11). Prepared-food sources may be an important venue for efforts to reduce obesity and risks for other chronic diseases. In the past several decades, multiple interventions were conducted in venues that provide prepared foods. One review (12) showed that interventions had success in private prepared-food–source environments, such as worksite and college cafeterias. However, no systematic reviews examined prepared-food source interventions in public community settings such as carryout, fast-food, and sit-down restaurants, even though prepared-food sources are more numerous in public settings than in private settings, and low-income individuals may have little access to private settings, which may offer more healthful options. The objective of this study was to systematically review community-based interventions in prepared-food sources that aimed to increase access to and consumption of healthful foods.

This systematic review was designed to identify interventions in public prepared-food sources; to present data on strategy, study design, evaluation, process indicators, and impact for each intervention identified; and to suggest next steps in research, practice, and policy. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, which provide 27 checklist items that aim to standardize the structure of meta-analyses and ensure comprehensive reporting (13).

Of the 13 interventions (15–49) that met the inclusion criteria, 12 interventions (15–18,21,22,24–35,37–41,45–48) were described in peer-reviewed publications. Personal communications (e-mail correspondence, telephone interviews) (n = 11) (15–27,30,31,37–49), informal documentation (reports, intervention materials) (n = 5) (19,20,26,43,44,49), and websites (n = 5) (23,36,42,43,49) were also sources of information (Table 1a, 1b, 1c, 1d).

This is the first systematic review of interventions in community-based prepared-food sources. Results are promising, showing that cost-effective methods (eg, labeling foods as healthful) may have a significant impact on prepared-food source sales and customer behavior. Most approaches centered on signage to promote existing healthful food choices. Several worked with kitchen staff to improve low-fat food preparation practices, and several conducted formal menu analyses to determine more healthful choices for promotion. These strategies, though resource intensive, show that it is important to engage prepared-food source staff in determining more healthful options.

Although interventions in prepared-food sources are increasingly being considered viable public health interventions, it is clear from this review that the evidence base for these interventions is deficient. Study designs tended to lack comparison groups, treatment conditions were not randomly assigned, and selection criteria were not readily apparent; these inadequacies cast doubt on the generalizability of findings.

Many of the interventions included in this review were not formal studies but rather certification or campaign programs operated by local health departments. These programs were voluntary, which may explain why they varied in levels of reach. Low reach may have been due to the actual burden placed on restaurant owners by the intervention or the lack of potential benefits perceived by them. Partnerships between local public health departments and academic institutions may help overcome some of these limitations through improved social marketing of program strategies and benefits. For example, local public health departments could initiate the intervention and manage recruitment while an academic institution partner conducts a full impact assessment, including psychosocial surveys and sales data collection.

We found no clear preference for a conceptual or behavior-change framework. A few interventions used social marketing approaches, but these interventions generally did not incorporate key social marketing components, such as formative research, audience segmentation, or targeting of messages (50). New frameworks for operationalizing prepared-food source interventions need to be developed; such frameworks should incorporate elements of theories on the food environment (51,52) and behavior change.

Although many interventions showed promising results, most lacked adequate measurement of the impact of the intervention on consumers. Of studies that examined consumer outcomes, most assessed only awareness of the health promotion campaign and food purchasing frequency. More sophisticated assessments — based on behavior-change theories — are needed to evaluate such outcomes as food purchasing patterns and dietary intake.

Almost half of the interventions lacked formal formative research — a major omission, especially considering that food environment research is an emerging area of public health programming. Formative research involves qualitative and quantitative data collection, which aids in program development (53–56); many interventions in our study would have benefited from this kind of preliminary research. In addition, most interventions focused only on promoting existing healthful options at prepared-food sources. Only 1 intervention sought to introduce new, more healthful foods. Interventions need to pay more attention to actively changing the food environment in prepared-food sources by increasing the availability of healthful food options.

Another approach worth exploring is price changes. Two interventions showed positive results by reducing food prices (Baltimore Health Carryouts [15–23] and Horgen and Brownell [27]). Ample evidence supports the use of price reduction as a means of promoting more healthful options among consumers (57–59). Moreover, research on pricing may support the hypothesis that the increased prevalence of obesity may be attributed to greater consumption of soda and chips that have artificially low prices because of government subsidies for corn and soybeans (4,60,61). If nonhealthful and healthful food prices were comparable, consumers might be more likely to purchase healthful foods. Baltimore Healthy Carryouts demonstrated that reducing the price of healthful foods not only increased sales of healthful foods but also increased total carryout revenue (17,20).

Our findings parallel in many ways the findings of recent interventions in small retail food stores (14). Both types of interventions focused on modifying the food environment and promoting healthful choices through point-of-purchase materials. A key difference, however, was that most research on small food stores has focused on food deserts in primarily low-income racial/ethnic minority populations. Only a few of the interventions in our study took place in low-income settings. More carefully evaluated interventions in food sources in low-income settings are needed. The high rates of obesity and other chronic diseases are related not only to the availability of healthful choices in retail food stores but also to access to healthful foods in prepared-food sources (15,62–64). Although a recent longitudinal study (63) showed mixed results on the relationship between the availability of grocery stores and diet-related outcomes, it demonstrated that the availability of fast food was related to fast food consumption in a low-income population. Low-income populations tend to rely on local prepared-food sources because they often work more than one job and do not have time to cook at home (65). One study found that during the 2007–09 recession, the middle quintile of households (the middle 20% of the income distribution) cut spending on food away from home by 20%, whereas the lowest quintile of households cut such spending by 12%, suggesting a greater reliance on food away from home among lower quintile households (66). Improving the availability of healthful food in prepared-food sources may be an effective way to promote dietary improvement in low-income settings.

This systematic review has some limitations. Many of the interventions reviewed were implemented by health departments that lacked the resources to conduct comprehensive evaluations and publish the findings in peer-reviewed publications. Thus, we included findings from the gray literature. Because of the wide variability in measures used and in impact assessments, we were not able to develop summary estimates or compare measures or impacts directly among interventions. These limitations emphasize the need for standardization of measures used by interventions and the need for further reviews that assess different strategies (14).

Our review lays the groundwork for further exploration of strategies to increase more healthful food options in community-based prepared-food sources. Many interventions showed that changing the prepared-food environment may improve sales and awareness of more healthful foods and improve purchasing and consumption behaviors. Interventions can be strengthened through comprehensive formative research and quantitative assessments of process and impacts. With these additions, future studies will be able to assess the relative effectiveness of different strategies and create standards of practice in prepared-food sources.