Modelling the Food Availability and Environmental Impacts of a Shift Towards Consumption of Healthy Dietary Patterns in Australia

TLDR

Dietary change is key to maintaining food security, improving health, and reducing environmental impacts amid rising populations, resource scarcity, and climate change, especially in developed countries. The study models the food availability and environmental impacts of shifting the average Australian diet to two healthy patterns: a mixed diet with animal and plant foods, and a plant‑based diet with only plant foods. Both diets were built per Australian Dietary Guidelines and four sustainability principles, assuming domestic supply where possible and exporting surplus, and their impacts on food availability, water, land, GHG, fuel, energy, and fertilizer use were compared. The plant‑based diet yielded the best overall environmental and food availability outcomes but faced fertilizer and land constraints; overall dietary shifts had minimal effect on the Australian agricultural sector and economy, underscoring the need for production and sectoral changes.

Abstract

Dietary change has been suggested as a key strategy to maintain food security, improve health and reduce environmental impacts in the face of rising populations, resource scarcity and climate change impacts, particularly in developed countries. This paper presents findings from a quantitative modelling analysis of food availability and environmental implications of shifting the current average Australian dietary pattern to one of two alternative, healthy dietary patterns, the ‘healthy mixed diet’, with a mixture of animal and plant foods, and the ‘healthy plant-based diet’, with only plant foods. Both were constructed in accordance with the Australian Dietary Guideline recommendations, and four sustainability principles: Avoiding over-consumption, reducing intake of discretionary foods, reducing animal products, and reducing food waste. It was assumed that all food was provided domestically where possible, and export of foods only occurred when there was a surplus to domestic requirements. The authors compared the impacts of each dietary pattern on direct food availability, water use, land use, greenhouse gas emissions, fuel and energy use and fertiliser use. The plant-based diet had the best overall environmental and direct food availability outcomes, however had key vulnerabilities in terms of fertiliser and cropping land availability. For the agricultural sector overall, changes in diet had little effect on environmental impact due to the amount and nature of Australian exports, indicating that changes to production methods are also necessary. Likewise, changing diets had little effect on the existing environmentally intensive Australian economy, indicating that changes to other sectors are also necessary.