ReviewDo school based food and nutrition policies improve diet and reduce obesity?
Introduction
Increasing attention has been paid to the role of schools in promoting healthier diets in children as a result of the rise in overweight and obesity among young people worldwide. The school environment has the broad potential to impact on students' food choices and dietary quality (Story, 1999, Kubik et al., 2003). Several environmental factors contribute to poor dietary habits during school time, such as lack of compliance with nutrition standards for lunch programs (Nelson et al., 2007) and easy access to foods of minimal nutrition value (known in the USA as competitive foods) at school (French et al., 2003, Neumark-Sztainer et al., 2005) which can be defined as foods high in added sugars, fats, calories and/or sodium (such as soft-drink, biscuits and sweets), but low in healthy nutrients, that are commonly sold in vending machines, canteens and other school locations (Fried and Simon, 2007).
In recent years, environmental and policy changes in the school settings are one of the most frequently proposed measures to address childhood obesity (Gostin, 2007, Swinburn et al., 2004). Unlike public health and education interventions that target individual behaviour change, school food and nutrition policies focus on changing the school food environment which is hypothesised to improve opportunities for healthier food choices for the whole student population (Wechsler et al., 2000, Masse et al., 2007). International proposals supporting the implementation of school programs include the World Health Organization Nutrition-Friendly Schools Initiative (WHO, 2006), and the Center for Disease Control and Prevention guidelines for school health programs to promote lifelong healthy eating (CDC, 1997). In recent years, countries worldwide have introduced a range of policies targeting the school food environment (Scotland. HM Inspectorate of Education, 2007, Victoria. Student Learning Division. Department of Education, 2007, Brasil. Ministério da Saúde. Ministério da Educação, 2006, Brasil. Ministerio da Saúde, 2007, Alberta, 2007, UK. Department for Education and Skills, 2007, Weber, 2007).
Previous reviews of the evidence have tended to focus on individual-level interventions to improve children's diet or prevent obesity (Summerbell et al., 2005, Knai et al., 2006, Hawkes, 2007, Peterson and Fox, 2007, Sharma, 2007). There has been very little research on the impact of policies, including those in schools. We systematically reviewed the evidence on the effectiveness of school-based nutrition policy on the food environment, and student's dietary intake and body mass index (BMI).
Section snippets
Criteria for considering studies
We carried out a literature search of published and unpublished studies of food or nutrition policies in preschools and school settings. We considered three categories of nutrition policy which we defined as: (i) nutrition guidelines: nutrition standards for menu planning based on food and/or nutrients and applied at school meal programs or at other meals sold in school environment; (ii) regulation of food and beverage availability: restrictive nutrition policies to limit access to unhealthy
Results
Of the 528 unduplicated papers identified from the search strategy (287 hits from Pubmed, 197 unduplicated hits from CAB abstracts, 44 from Web of Knowledge and 2 from the Cochrane Library), 49 reported on implemented school nutrition policy, based on screening of titles and abstracts. A further 22 articles were excluded as they did not meet our inclusion criteria. The final pool consisted of 27 papers reporting on 18 studies. Studies found through tracking of references and contacting experts
Discussion
Schools have been promoted by policymakers, researchers and media as a logical strategic setting for implementing nutrition policies aiming at promotion of healthy diet and tackling childhood obesity. This review shows that the current evidence of effectiveness is limited, and no studies of cost-effectiveness were identified.
This review is not intended to conclude what type of school-based nutrition policy should be implemented, but aims to synthesise the available evidence, identify evidence
Conclusion
This review synthesises the evidence of effectiveness of school food and nutrition policies. Evidence suggests that nutrition guidelines and price interventions focused on healthier foods are effective to improve the school food environment and students' dietary intake. However, it is interesting that there was very little evidence, and lack of consistent findings for the effectiveness of regulations of food and beverage availability; and there are currently few studies which have measured the
Acknowledgments
We are grateful to International Nutrition Foundation and Ellison Medical Foundation for the post-doctoral fellowship to PC Jaime at London School of Hygiene and Tropical Medicine. We are also grateful to all experts and stakeholders contacted during the search for grey literature.
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