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Is a sustainable diet sustainable for your wallet?

Sophie Mahoney

We’re told to reduce, reuse, recycle when it comes to sustainability, yet despite our food systems being one of the leading causes of environmental damage, how often is our diet in the conversation when it comes to taking care of the planet?

Through deforestation, carbon and methane emissions, food waste and plastic packaging, agriculture and food production threaten our climate and ecosystems. What’s more is that our current diet is not only bad for the environment, but also our health. This makes what we eat an important leverage for optimising human and planetary health.

In 2019, the EAT-Lancet Commission, driven by 37 leading scientists across the globe, created the world’s first guidelines for healthy and sustainable diets, known as the Planetary Health Diet (PHD). The diet recognises there needs to be significant shifts in the way we eat going forward, including a more than doubling in the consumption of fruits, vegetables, legumes and nuts, as well as a greater than 50% reduction in added sugars and red meat. For example, the target daily red meat consumption of 14 grams is a stark comparison to the 80g per day (29kg annually) currently eaten by the average Australian.

The PHD, rich in plant-based foods with fewer animal-based products, will ensure both environmental and health benefits, with an estimated 11 million deaths prevented each year.

However, nutrition is only one of several factors that drive our food choices, along with accessibility, availability, food preferences, and of course, affordability. For the PHD to be acceptable by Australian consumers, it needs to have a comparable cost to our current diet, which often takes priority over other factors.

Many people perceive health eating as being expensive, which the food industry is partly to blame for. “Health foods” promoted by industry are often more expensive than their equivalents in supermarkets, like high-protein yoghurt, gluten-free substitutes, fermented foods and those filled with artificial sweeteners.

To assess the affordability of the PHD, Australian researchers have analysed the cost compared to a typical Australian diet. The Australian-PHD food basket included items such as brown rice, nuts, wholemeal bread, oats, fruits, vegetables and legumes, with only a small amount of meat, mostly from lean sources such as poultry and fish.

The researchers found that the PHD basket was less expensive and more affordable than the Typical Australian Diet all across Australia, including metropolitan, regional and rural areas and in all socio-economic groups.

In some countries, sustainability is now being considered in national nutrition guidelines, through prioritising plant-based eating, consuming seasonal and local foods, reducing food waste, and reducing consumption of unhealthy foods such as red and processed meat, ultra-processed foods and sugar-sweetened beverages. Therefore, the results of this research can help inform public health and food policy for a healthy and sustainable diet for all Australians.

This way of eating will have a lower environmental impact than our current diets, while contributing to food security and meeting the health and nutritional needs of our population.

Sophie is a Research Assistant at the Food & Mood Centre, working on the TANDIM project. She is an Accredited Practising Dietitian with research interests in Irritable Bowel Syndrome and common mental disorders.