Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Nutrient-adequate diets with the lowest greenhouse gas emissions or price are the least acceptable—insights from dietary optimisation modelling using the iOTA model®(Frontiers Media S.A., 2025-08-01) Tavan M; Smith NW; Fletcher AJ; Hill JP; McNabb WC; Das AOver the past decade, there has been an increasing interest in the environmental sustainability of diets because food systems are responsible for a third of the anthropogenic greenhouse gas emissions (GHGE). However, less attention has been paid to the nutrient adequacy, consumer acceptability, and affordability of such diets. Such knowledge is particularly scarce in New Zealand, where approximately 40% of adults and 20% of children may live under severe to moderate food insecurity. The iOTA Model® is a country-specific dietary optimisation tool designed to fill this gap by bringing the various aspects of diet sustainability together and providing evidence-based knowledge on not just the environmental impact of food but also its economic and nutritional sustainability. The iOTA Model® was constructed using mixed integer linear programming by integrating New Zealand-specific dietary data. Features such as digestibility and bioavailability considerations have been incorporated as part of the iOTA Model®, allowing for a more accurate estimation of nutrient supply. The model is available as an open-access tool and allows users to explore various dimensions of a sustainable diet. Eight optimisation scenarios, along with baseline diets, were investigated for adult males and females in New Zealand. Results showed that reducing dietary GHGE or price by approximately 80% was possible while meeting nutrient adequacy requirements. However, such diets deviated substantially from the baseline eating patterns, indicating lower consumer acceptability, and only included a limited variety of foods. On the contrary, diets with minimum deviation from baseline remained realistic while adhering to nutrient targets and reducing GHGE by 10 and 30% in female and male consumers aged 19–30 years, respectively, and weekly price remained below the baseline. Expansion of the model to additional countries and its open-access nature will allow independent dietary sustainability research through optimisation.Item Animal and plant-sourced nutrition: Complementary not competitive(CSIRO Publishing, 2022-05) Smith NW; Fletcher AJ; Hill JP; McNabb WC; Pembleton KDebate on the sustainability of the global food system often compares the environmental, economic and health impacts of plant- and animal-sourced foods. This distinction can mask the considerable variation in impacts across and within these food groups. Moreover, the nutritional benefits of these food groups are insufficiently discussed. In this review, we highlight the nutritional contribution to the current global food system of both plant- and animal-sourced foods and place their impacts on human health in the global context. We highlight how the comparison of the environmental impacts of foods via life cycle analyses can change on the basis of the functional unit used, particularly the use of mass as opposed to nutrient content or nutrient richness. We review the literature on the affordability of nutrient-adequate diets, demonstrating the presence of both plant- and animal-sourced foods in affordable nutritious diets. Finally, we address the potential of alternative food sources that are gaining momentum, to ask where they may fit in a sustainable food system. We conclude that there is a clear place for both plant- and animal-sourced foods in future sustainable food systems, and a requirement for both for sustainable global nutrition; as such, the two groups are complementary and not competitive.