Trimming the excess: environmental impacts of discretionary food consumption in Australia

•An approach to estimate environmental impacts of discretionary foods is presented.•Discretionary foods account for 33-39% of food-related footprints in Australia.•Reducing these environmental impacts is more challenging for poorer households.•Attempts to promote healthy and sustainable diets must ensure equitable outcomes.

Tackling the overconsumption of discretionary foods (foods and drinks not necessary to provide the nutrients the body needs) is central to aligning human and planetary health. Whilst the adverse health impacts of discretionary foods are well documented, the environmental and broader sustainability impacts of these products deserve more attention, especially since their consumption has been increasing in recent decades, particularly amongst low income groups. This paper presents a quantitative case study analysis of discretionary food consumption and the associated environmental impacts for households from different income groups in Australia. Environmentally extended input-output analysis is used to estimate the full life cycle environmental impacts of discretionary food consumption on the basis of household expenditures. On average, discretionary foods account for a significant 35%, 39%, 33% and 35% of the overall diet-related life cycle water use, energy use, carbon dioxide equivalent and land use respectively. These significant percentages provide further support for the need to incentivise diets that are both healthier and more sustainable, including 'divestment' from discretionary food products. The study highlights the challenges ahead, including the need for further research on food substitutions to minimise environmental and social impacts whilst maximising nutritional quality - especially amongst poorer socioeconomic groups.