Abstract:
Background: The World Health Organization has acknowledged that increased consumption of packaged, typically heavily processed, convenience foods is a significant cause of obesity and non-communicable diseases globally. Evidence indicates growing dominance of packaged (processed) foods in local consumer food environments, including supermarkets where New Zealanders make the majority of their weekly food purchases. However, the implications of widespread availability of heavily processed foods are typically ignored when developing nutrition recommendations and public health policies. Aim: To undertake a systematic review of the international literature on relative availability of fresh and packaged foods in supermarkets, and to measure total product counts and shelf space allocated to fresh and packaged foods in New Zealand food retail stores. Methods: A systematic literature review of the absolute availability (i.e. shelf space and/or product count) of fresh and/or packaged foods was performed using four medical and health related databases, Embase, Medline, PubMed, and Scopus. Search strategies were adapted for each database and consisted of the MeSH terms fruit, vegetables, “food, preserved”, and “food supply”, along with other key terms including “fresh food”, “healthy foods”, “processed foods”, “packaged food”, “unhealthy food”, supermarket, “food store”, “convenience store”, “grocery store”, availability, “shelf space”, and proportion or percentage. Additionally, a cross-sectional in-store audit of shelf space and product counts of all foods in two supermarkets, one convenience store, and one online supermarket (i.e. grocery shopping website) was undertaken in two socioeconomically disadvantaged Auckland neighbourhoods between September 2015 and April 2016. Individual foods were classified by level of processing using Monteiro’s 2010 taxonomy (fresh and minimally processed, culinary processed, and ultra-processed). Findings: The systematic literature review resulted in 10 studies that reported some quantitative measure of availability of fresh and/or packaged foods and included studies conducted in eight countries (United States (n=6), Australia (n=4), New Zealand (n=2), United Kingdom (n=1), Canada (n=1), Denmark (n=1), the Netherlands (n=1), and Sweden (n=1)). Overall, less healthy, packaged foods were found to be available in greater proportions (2 to 74 times greater) than healthier, fresh foods across all store types and social gradients. The in-store audits found greater proportions of packaged foods compared to fresh in all food retail stores surveyed (n=4). Ultra-processed foods comprised 79 percent of shelf space area in-store and 82 percent by product count in-store and online, whereas fresh food by shelf space area was six percent and by product count was three percent. The differences between the proprotions of foods available by level of processing were statistically significant (Kruskal-Wallace-H test H(2) = 8.537, p < 0.05; Chi-square of percentages p = 0.000). Conclusion: Ultra-processed, packaged foods are significantly more available than fresh foods in supermarket food environments. With strong evidence implicating diets comprised of heavily processed foods as a significant contributor to the rising prevalence of obesity and related NCDs, public health interventions that target the emphasis on these foods in supermarkets are needed (e.g. incentives to store owners for supplying and promoting healthier, less processed foods).