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

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.