Millions of people around the world are hitting the streets this year in support of students who are demanding an end to fossil fuels. But we can also strike with our forks: global food production contributes around a quarter of greenhouse gas emissions.

Australia was recently flagged as one of the countries with the greatest potential to reduce diet-related greenhouse gas emissions.

The Intergovernmental Panel on Climate Change (IPCC) declared that it is crucial for all sectors to rally against global heating, and targets to slow it down simply can’t be achieved without addressing food production and land management.

Environmental degradation also goes hand-in-hand with the global pandemic of chronic diseases including obesity, diabetes, cancer and heart disease. This double whammy includes other factors associated with industrial monocrops, such as pesticides and fertiliser.

So tweaking dietary habits is a win-win for people and the planet. But just what would a climate-friendly diet look like?

Meat would feature less

Meat and dairy are two primary contenders, according to the IPCC – cattle production is a major source of methane emissions and deforestation. This is particularly relevant for Australians who relish their steaks and sausages – they are the world’s second biggest meat eaters.

Given that more than one in 10 people – and rising – is vegetarian some of us are eating an awful lot of animal flesh. In fact, Australian meat consumption has grown from 93kg to nearly 95kg per person each year – that’s equivalent to everyone eating a very large steak every day.

“The mass production of meat is the single biggest cause of land clearing around the world, if not directly for the animals themselves then indirectly for the monocultures such as corn or soy that feed them,” says economist Dr Gillian Hewitson from the University of Sydney.

Sustainability expert Dr Michalis Hadjikakou, from Deakin University, Melbourne, agrees that reducing meat is a good start, but acknowledges radical shifts to vegan or vegetarian diets are difficult for many. For those who struggle, he suggests cutting back on beef and lamb, meats with the biggest environmental footprint.

Other more sustainable options include kangaroo meat – which is harvested wild under strict quotas and is becoming increasingly popular. Wild rabbit is another eco-friendly option that is making its way back onto Australian menus.

Insects such as mealworms and crickets are also climate-friendly alternatives, for those who can stomach them. If not, other viable non-meat protein sources abound, including legumes, nuts, seeds (think quinoa, chia), wholegrains, eggs – and even nutty-flavoured hemp.

Vegetarians might need to rethink too

New research is making it harder to gloss over dairy’s impact, suggesting that swapping out bacon for haloumi is not much gentler on the planet.

The study models country-specific dietary changes that could alleviate our climate, water and health crises.

Overall, it confirms that bovine, sheep and goat meats have by far the highest environmental impact. But eating certain animal products once a day has a smaller footprint than lacto-ovo vegetarian diets that exclude meats but include dairy foods.

The small footprint of this “low-food-chain” diet, in which insects, forage fish and mollusks replaced a large chunk of terrestrial and aquatic animals, was second only to vegan diets.

A diet incorporating low-food-chain animals such as mussels and other mollusks can be almost as environmentally beneficial as veganism. Photograph: Karen Robinson/The Observer

Plants would feature more

In any event, switching to more plant foods is considered paramount for planetary and human health – especially as most Australians don’t eat enough of them.

Plant foods are staples of traditional diets, and the much-researched Mediterranean diet – rich in vegetables, fruit, legumes, nuts, seeds, wholegrains and extra virgin olive oil – delivers multiple health benefits with its kaleidoscope of nutrients and fibre. As a bonus, Australians can grow pretty much anything that thrives in Mediterranean regions – even in our own backyards – and research has shown this diet is both viable and easy for Australians to adopt.

A wider variety of plants would be eaten

Possibly some of the most sustainable – and nutritious – foods could be growing wild in our backyards or footpaths: edible weeds. Most cities even have guided foraging tours to help residents find them. Gardening expert Kate Wall, for instance, runs regular weed workshops in Brisbane that explore which weeds are edible and what can be done with them. “We have a forage and together we create a three-course meal with drinks, all based on weeds,” she says.

Over tens of thousands of years, the keen eyes of Indigenous Australians have unearthed this large island’s abundance of nutritious, edible native plants that are adapted to our parched climate. From bush tomatoes and desert limes to Kakadu plums, quandong and riberries, there are potentially thousands of species to be widely adopted.

Desert quandong, an edible plant native to Australia. Photograph: Auscape/UIG via Getty Images

Eating seasonal foods grown locally and avoiding imported foods can be another way to support the environment. There are, however, some contingencies depending on how it’s grown – for instance, indoor farms that rely on artificial sunlight may be hyper-local, but they’re not very energy efficient. Locally grown foods also tend to be fresher than transported and stored produce – and more nutritious, possibly making them even more important than eating organic, according to experts.

We’d eat less overall

Quality is more important than quantity, says Dr Mario Herrero Acosta, chief research scientist at CSIRO, and IPCC contributor.

Eating less will help maintain a healthy weight and put less pressure on Earth’s resources. The same goes for buying less: about a third of all food produced is never eaten, wasting precious land, water and energy used to produce it. If it were a country, the amount of greenhouse gases emitted by food waste would be just behind the US and China.

The simplest thing that Acosta thinks people could do right away, therefore, is to “eat and buy mindfully, meaning to eat less discretionary foods and ensure the minimum goes to waste”.

Junk food would be binned

Cutting back on junk foods and drinks – highly processed products teeming with sugar, salt and unhealthy fats – would make a big difference, says nutritionist Dr Rosemary Stanton. Tackling these “discretionary” items that are unnecessary for a healthy diet is not only critical for human but also planetary health. Hadjikakou calculated that producing junk food contributes to more than a third of Australia’s food-related environmental impact, in terms of their water and land use, energy consumption and greenhouse gas emissions.

This also applies to processed vegan foods, adds Stanton, so simply going vegan without considering other health and environmental factors is not a sustainable solution. And although tinned lentils and vegetables are healthier options and considerably more sustainable to grow, cooking them in their whole form would avoid the environmental resources needed to package them.

And home cooking would make a comeback

Australia has become a “takeaway nation”. While we love watching celebrity chefs cook, increasingly Australians shun our own stoves in favour ordering in or going out. In just 10 years, the money Australians spent on eating out doubled to a whopping $3.5 billion.

Reviving home cooking in Australia would promote good health while lowering the destructive impacts of industrial food production and packaging.

This is not just for the privileged. While poorer people tend to eat more takeaway and processed food, research shows that a healthy, plant-based diet is not only affordable, but cheaper than the typical Australian diet.



