Sustainability and cost of typical and heart-healthy dietary patterns in Australia

Study objective
The aim was to quantify and compare the environmental and financial impact of two diets: a heart-healthy Australian diet (HAD) and the typical Australian diet (TAD).
Design
The study involved a secondary analysis of two modelled dietary patterns used in a cross-over feeding trial.
Setting
The evaluation focused on two-week (7-day cyclic) meal plans designed to meet the nutritional requirements for a reference 71-year-old male (9000 kJ) for each dietary pattern.
Main outcome measures
The environmental footprint of each dietary pattern was calculated using the Global Warming Potential (GWP*) metric, taking into account single foods, multi-ingredient foods, and mixed dishes. Prices were obtained from a large Australian supermarket.
Results
The HAD produced 23.8 % less CO2 equivalents (CO2-e) per day (2.16 kg CO2-e) compared to the TAD (2.83 kg CO2e per day). Meat and discretionary foods were the primary contributors to the environmental footprint of the TAD, whereas dairy and vegetables constituted the largest contributors to the HAD footprint. However, the HAD was 51 % more expensive than the TAD.
Conclusion
Transitioning from a TAD to a HAD could significantly reduce CO2 emissions and with benefits for human health and the environment. Affordability will be a major barrier. Strategies to reduce costs of convenient healthy food are needed. Future studies should expand the GWP* database and consider additional environmental dimensions to comprehensively assess the impact of dietary patterns. Current findings have implications for menu planning within feeding trials and for individuals seeking to reduce their carbon footprint while adhering to heart-healthy eating guidelines.