A conceptual framework for understanding the environmental impacts of ultra-processed foods and implications for sustainable food systems
Introduction
Food system transformation offers a powerful opportunity to collectively address all components of sustainability, namely the economic, social, environmental and health impacts of food production and consumption(FAO, 2018). The global food system is one of the largest drivers of global environmental change(Tilman and Clark, 2014; Willett et al., 2019) but it is failing to provide adequate nutrition for a large proportion of the world's population(FAO et al., 2019).
Sustainable food systems provide the foundation for sustainable diets by enabling access to healthy and sustainable foods. The FAO description of sustainable healthy diets encourages consumption of wholefoods, such as fruit, vegetables and wholegrains(FAO and WHO, 2019). The guidelines also state that healthy and sustainable diets can include moderate amounts of eggs, dairy, poultry and fish; and small amounts of red meat … while restricting highly processed food and drink products(FAO and WHO, 2019), also known as ultra-processed foods (UPFs). UPFs are defined as ‘formulations of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes’ and contain little or no whole foods(Monteiro et al., 2019).
Evidence for the environmental and health benefits of reducing consumption of animal-based products is well-established(Godfray et al., 2018). In contrast, research on the environmental impact of UPFs is limited. While processing is key to food safety and security(Augustin et al., 2016), there is a growing concern that UPFs are processed beyond what is necessary for food safety, with adverse impacts on human health(Elizabeth et al., 2020), and probable adverse environmental impacts(Fardet and Rock, 2020).
The manufacture and consumption of UPFs are rising(Baker et al., 2020) and existing literature has reported that this can impact the social(Monteiro et al., 2018), health(Elizabeth et al., 2020) and economic(Oxfam, 2013) dimensions of sustainability. UPFs can change the social aspect of eating by replacing shared experiences relating to acquiring, preparing, cooking and eating local and traditional foods with eating ready-made ubiquitous foods alone, and may encourage mindless eating(Monteiro et al., 2018). These changes in eating have also been reported to redirect finances away from the smallholder production of unprocessed and minimally processed foods to ready-to-eat UPFs sold by large transnational corporations (Baker et al., 2020; Hadjikakou and Wiedmann, 2017; Monteiro et al., 2018). This can contribute to economic inequalities as some large trans-national corporations responsible for UPF production rely on underpaid food system workers in poor conditions, resulting in an uneven distribution of wealth(Oxfam, 2013). In high-income countries, UPFs are disproportionately consumed by lower-socioeconomic groups, which may exacerbate existing economic, health and social inequalities(Baker et al., 2020; Fardet and Rock, 2020).
UPFs utilise persuasive marketing and are usually mass-produced using inexpensive ingredients to enable overconsumption through availability, hyper-palatability, poor satiety and displacing wholefoods in diets(Monteiro et al., 2018). A growing body of evidence reports that UPF consumption is associated with increased risk of overweight and obesity, cardiovascular diseases, type-2 diabetes, metabolic syndrome, irritable bowel syndrome, cancer, depression, and all-cause mortality, among others(Elizabeth et al., 2020; Lane et al., 2021). It is plausible that this is caused by UPFs poor nutrient composition and degraded food matrices(Fardet, 2016).
Despite the growing body of evidence for the health, social and economic impacts of UPFs, their environmental impacts remain poorly described and quantified within the scientific literature. Four commentaries/syntheses(Clark et al., 2020; Monteiro et al., 2018; Scott, 2018; Seferidi et al., 2020) and a narrative-style review(Fardet and Rock, 2020) have conceptually explored aspects of the environmental impact of UPFs. These studies have proposed that UPF production can impact the environment through reliance on practices such as large-scale monoculture farming, deforestation and biodiversity loss(Monteiro et al., 2018). They suggest that UPF manufacturing and distribution require considerable energy inputs and thus contribute to greenhouse gas emissions, and other waste(Seferidi et al., 2020). Finally, the studies have noted that UPFs rely on large multinational supply chains which are likely to result in transport, waste and packaging-related environmental degradation(Seferidi et al., 2020). However, existing commentaries, syntheses and reviews are not comprehensive; they are based on limited studies, do not present findings according to the lifecycle of products throughout the food system and have not considered the implications of different terms, which encompass foods that can be considered UPFs (such as many discretionary foods and foods high in fat, salt and sugar), used to classify such foods on study results.
A detailed understanding of the environmental impacts of UPFs is key to informing food policies and dietary guidance. This is pertinent because UPFs are frequently excluded from global and national guidelines and policy documents on sustainable food systems and diets. For example, the EAT-Lancet report, one of the most recognised reference documents on sustainable diets, does not mention UPFs(Willett et al., 2019), nor does the major FAO report on the biodiversity impacts of food and agriculture(FAO, 2019). The few policy activities which consider the environmental sustainability of UPFs are based on conceptual evidence, rather than evidence from empirical studies. Thus, better understanding the empirical evidence on this topic is important to inform future food policies and dietary guidelines for sustainable food systems.
This review aims to determine the types of environmental impacts resulting from each stage of UPF production, and the magnitude of these impacts in the context of dietary consumption patterns. In addition, the review summarises methods used to measure the environmental impacts of UPFs, and the terms and definitions used to describe UPFs in environmental sustainability research. While it was not the focus of this paper, impacts on social, health and economic sustainability which were measured or described in the included studies are also discussed.
Section snippets
Methods
A narrative review approach was adopted to capture the complex themes and diverse study methodologies within this field of research(Popay et al., 2006). Rigour was maintained by using a systematic search strategy and structured results tables. The review followed four steps: 1) a systematic search for literature, 2) study screening, 3) data extraction, 4) data analysis and synthesis.
A conceptual framework of the environmental impacts of UPFs
This section summarises the environmental impacts of UPFs as described or measured in the included studies. An overview of the results is also presented in the conceptual framework (Fig. 2) which describes the sustainability implications of UPFs throughout the food supply chain. Table 1, Table 2, Table 3, Table 4, Table 5 display the key results for each environmental issue addressed in the included studies. Further details for each study can be found in Appendix B. While this review focused on
Discussion
This review aimed to summarise evidence on the environmental impacts of UPFs, including the terms and definitions used to describe UPFs in environmental sustainability research and methods used to measure the environmental impact of UPFs. The foods included in this review either met the criteria to be classified as a UPF under the NOVA classification scheme or the context in which they were used was consistent with how UPFs are defined(Monteiro et al., 2019). The findings of the review can be
Conclusion
Ultra-processed foods are fundamentally unsustainable products; they have been associated with poor health and social outcomes and require finite environmental resources for their production. This review developed a novel framework to visualise and track the environmental impacts of UPFs at key stages throughout the food system.
The review also reported the magnitude of UPF-related impacts and found that UPFs are responsible for significant diet-related energy, greenhouse gas emissions, land
Authorship
Kim Anastasiou: Conceptualisation, Methodology, Study screening, Writing- Original Draft. Phillip Baker, Michalis Hadjikakou, Gilly Hendrie, Mark Lawrence: Conceptualisation, Methodology, Writing- Review & Editing.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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