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Ultra-Processed Foods and Single-Use Plastic Packaging in Home-Packed School Lunchboxes: A New Zealand Study

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2023

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Thesis

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Master of Public Health

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Auckland University of Technology

Abstract

Globally, two-thirds of children experience the triple burden of malnutrition, encompassing undernutrition, micronutrient deficiencies, and overweight/obesity. The excessive consumption of ultra-processed food and drinks (UPF) leads to dietary patterns lacking nutrient-dense wholefoods. UPF have been linked to various negative health outcomes including cardiometabolic risks and asthma, and the synthetic additives in UPF have been associated with immune and endocrine disruption. Moreover, highly-processed dietary patterns inherent to current food systems contribute to environmental degradation, including greenhouse gas emissions, plastic waste, land and water pollution, and biodiversity loss. Consequently, promoting sustainable healthy diets that nourish individuals while ensuring long-term ecological sustainability has become a priority across international public health agendas. School food environments are a key setting for promoting healthier diets among children. In New Zealand (NZ), home-packed school lunchboxes are the norm; however, research on the extent of UPF in home-packed lunchboxes in NZ is lacking, and there is limited knowledge regarding the eco-environmental impacts of these packed-lunches. Drawing upon the emerging literature in eco-nutrition, this thesis aimed to explore the healthiness and sustainability of lunchboxes in terms of their level of food processing and their environmental impact from single-use plastic packaging. To establish the context for this work, a narrative review was performed to cover two key areas: (1) the distinctive nature of UPF and their impact on human and planetary health, and (2) healthy and sustainable diets for children, with a focus on child-centred food systems, and schools as strategic intervention settings. The review highlighted the unique metabolic effects of UPF on gut and brain health, as well as concerns associated with excessive exposure to food additives, particularly in children. It also emphasised the need to update current dietary guidelines to consider the role of food processing, food matrix, and food sustainability, as well as the need to reorient existing food systems to meet children’s unique nutritional needs. The review further revealed that most school lunchboxes fail to meet dietary guidelines, and an absence of national dietary regulations and school-level lunchbox policies. A two-part cross-sectional study was undertaken, which included 110 children from four primary schools representing different socioeconomic deciles and regions in Auckland, NZ. Lunchboxes were digitally photographed and complemented with a Lunchbox Food Checklist. Part 1 of the study aimed to assess the level of food processing in home-packed lunches and investigate the relationship with the nutritional content (energy and sugar) of lunchbox items, while Part 2 aimed to determine the proportion of single-use plastic packaging waste in lunchboxes and examine the association with the level of food processing. In Part 1, the nutritional composition (total energy and total sugars) of lunchboxes was calculated, and lunchbox items were also categorised into one of three levels of processing (unprocessed/minimally-processed, processed, ultra-processed) based on the NOVA classification system. Statistical analyses explored differences in energy (kJ) and sugar (g) among the processing levels, while adjusting for school, gender, and who packed the child’s lunch (child, parent). Results revealed that UPF accounted for approximately two-thirds of the overall energy (61.8 ±27.0%), and half of total sugars (50.4 ±31.5%) in lunchboxes. Among the 599 food items (6.0 ±1.9 items per lunchbox), sweet and savoury UP snacks were the primary contributors to energy from UPF (40%), while there was a significant lack of minimally-processed foods (13.7±16.6%) in lunchboxes. Findings were consistent across genders, schools, and lunchbox packer (child/parent). For Part 2 of the study, the packaging of lunchbox food and drink items was categorised into four groups (single-use plastic, single-use other, reusable, no packaging), and two methods of packaging coding were employed to account for packaging removed from food at home. Analysis revealed that of 541 lunchbox packaging items, 35.6% were single-use plastic packaging (SUPP). However, when considering the original packaging (removed at home), the proportion of SUPP increased significantly to 53.2% (p < 0.001, g = 0.91). The majority of SUPP originated from UPF (76.2%), while minimally-processed foods contributed to only 0.9% of SUPP. Soft plastic bags/wrappers from UP snacks (58.8%) were the most prevalent type of SUPP in lunchboxes. Taken together, these results show that prioritising the inclusion of whole and minimally-processed foods in home-packed lunchboxes can reduce single-use plastic packaging waste while promoting healthier and environmentally-friendlier dietary patterns in school settings. Additionally, results underscore the need for updated dietary guidance for children that consider the impact of extreme food processing on the overall healthiness and sustainability of food choices. This body of work makes important contributions to existing literature. This is the first known study to explore the association between the level of food processing and packaging waste in lunchboxes. It provides valuable and credible data for future eco-nutrition-based research and interventions in school settings. This research contributes to the emerging field of child-centred food system research, which seeks to identify the types of foods children are currently consuming (or not consuming) to help reorient existing food systems towards increased availability and demand for healthier child-oriented product choices. Future research should prioritise gathering population-level data on children’s overall UPF consumption in NZ and investigate the environmental and social-economic determinants of lunchbox food choices. Exploring the potential eco-nutrition application of the ‘NOVA-SUPP’ model developed in this thesis could help foster healthier and more sustainable diets for children and improve planetary health.

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http://hdl.handle.net/10292/16877

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