The 2007 Institute of Medicine report, “Nutrition Standards for Foods in Schools: Leading the Way Toward Healthier Youth,” concluded that the federally reimbursable school meals program should be the primary source of nutrition at school and access to competitive food sources, which include vending machines and snack bars, should be limited and, when available, consist of nutritious items, such as fruits, vegetables, and nonfat or low-fat milk and dairy products (19
). School Health Policies and Programs Study 2006 found that the prevalence of vending machines and school stores had decreased somewhat compared to the School Health Policies and Programs Study 2000, especially in elementary and high schools (3
). Similarly, the nutritional quality of food and beverages offered to students from vending machines and school stores improved during this 6-year period, although items high in fat and added sugars remained among the most common items offered for sale to students (3
). Also during this time period, voluntary agreements with the beverage, snack, and dairy industries to provide healthier foods and beverages to schools were facilitated by the Alliance for a Healthier Generation (21
). Despite these advancements and a national concern about a childhood obesity epidemic that has been linked to increased availability and accessibility of low-nutrient, energy-dense food and beverages (22
), many US schools persist in providing vending machines and school stores that offer junk food for sale to students during the school day (2
). In the present study, among schools with vending machines and/or school stores, a large majority offered junk food for sale to students, including all high schools.
Findings from the current study suggest that state-level policy may be an effective tool to decrease junk food availability in schools, particularly among elementary and middle schools. Study results also indicate that policy rigor, defined as policy that required prohibiting junk food in vending machines and school stores, was associated with improved outcomes at the school level.
Significant or near significant associations at or near a P < 0.05 level were not apparent for district-level policies. This appears to be the result of less rigorous policy at the district level when compared to state-level policy. For example, 43% of schools were located in states that required schools to prohibit offering junk food for sale to students in vending machines and school stores. In contrast, only 22% of schools were located in districts with equally rigorous district policies. Similarly, only 4% of schools were located in states with inconsistent policies, defined as different junk food requirements for vending machines and school stores, whereas 26% of schools were located in districts with inconsistent policies. District policy makers have a more proximal association with schools than state policy makers, which may result in a more cautious or less rigorous approach to policy-setting and a tendency to defer meaningful rule-making responsibilities to officials at the local or school level. This hypothesis merits further evaluation, particularly given the federally mandated role of district administrators in setting nutrition policy for schools. The present study did not examine the concordance between state- and district-level policy and the association between policy concordance and rigor and school-level practice. Future research should consider this association as well.
The lack of an association between policy and junk food availability in vending machines and school stores among high schools at both the state and district level was not unexpected, given the almost ubiquitous presence of these popular food venues among the high school sample. Nevertheless, it is concerning that the associations seen among elementary and middle schools between rigorous state-level policy and junk food availability were not evident among high schools. There were essentially no differences between the most- and least-rigorous policies and junk food availability in high schools at both state-and district-levels. For high schools, these findings suggest that policy alone, especially policy established at levels distal to the school, is less likely to facilitate healthy change in junk food availability in vending machines and school stores. Successful, albeit short-term, interventions targeting the high school food environment have been few, and mostly demonstrated the benefits of involving local school staff and students in change strategies to increase availability of healthier food items, as well as manipulating price in favor of healthy food choice (26
). Successful, sustainable change in the high school food environment will likely require a combination of rigorous policy across school, district, and state levels, as well as local school-based efforts that engage school staff and students. This approach could also contribute to healthy change in middle and elementary schools.
This study has several strengths, including use of data collected from a nationally representative sample of elementary, middle, and high schools, which were linked to district- and state-level policy data collected as part of the School Health Policies and Programs Study 2006. This study is among the first to report on the association between state- and district-level policy prohibiting schools from selling junk food in vending machines and school stores and the availability of junk food in vending machines and school stores at the school level. The analysis approach allowed for the detection of differences in policy translation in elementary, middle, and high school settings and at state and district levels, which has important implications for policy makers.
Study limitations are the same as those described for the School Health Policies and Programs Study 2006 (12
). Although all state agencies participated in data collection, at the district and school level response rates were 74.5% and 77.9%, respectively. Among responding districts, participation in the nutrition services module was 64.5%. Among responding schools, participation in the healthy and safe school environment module was 72.4%. It is possible that districts and schools that participated were different by important characteristics from districts and schools that did not participate. Data collection occurred via self-report, which is subject to social desirability bias. In addition, although questionnaires were completed by designated respondents identified as most knowledgeable about the policies addressed in a particular questionnaire, it is possible that actual knowledge about a particular item was lacking or did not reflect current school practice (12
). A study assessing the reliability and validity of the School Health Policies and Programs Study 2000 questionnaires found that correspondence between survey questions and policies was generally good; however, threats to validity of some items on the district and state questionnaires and reliability of select items on the school-level questionnaires were identified (29
). Finally, given the cross-sectional nature of this study, a causal link between policy and junk food availability cannot be established.
In conclusion, vending machines and school stores that sell junk food to students during the school day are popular and pervasive food venues in US schools. This study suggests that the potential for policy to decrease junk food availability in these popular food venues is promising. Not surprisingly, policy rigor was associated with less junk food, especially in elementary schools, but also in middle schools. When setting policy targeting junk food availability in schools, school nutritionists and other health professionals who are in positions to contribute to the policy-making process are encouraged to consider policy rigor, as well as incorporate a process that engages school staff and students. This integrative approach can be especially beneficial in high schools, where prevalence of vending machines and schools stores is high and resistance to healthy change appears to be strong. Creating a healthy school food environment is challenging work that will continue to require the attention of many, including school nutritionists and other health professionals who are dedicated to developing and disseminating meaningful food policy that translates into healthy school practice.