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Sustainable diets: eating in harmony with the planet

Woman with dark hair smiling
11 min read
AUTHOR: Anna Turns
group of friends dining al fresco

Food sustainability incorporates many aspects. It’s about environmental impacts, carbon footprints and nature, but it’s also about the ethical and health effects on people. So deciphering what makes a truly sustainable diet is complicated. Depending on someone’s preferences and priorities, their location and buying habits, foods that make up a sustainable diet will vary.

A sustainable or ‘climavore’ diet encourages people to eat with the planet and its changing climate in mind – that includes locally-sourced, seasonal and organic produce, drought-resistant crops in a period of water scarcity, plus plant-based protein instead of beef. Essentially, it’s flexible and adaptive – as the climate changes, so too will the recommended foods. 

The simplest advice is to try to buy food with a story you know’. These wise words, from Patrick Holden, CEO of The Sustainable Food Trust and speaker at Food Matters Live’s Sustainable Food Forum this coming September, are a powerful reminder that, despite living within a globalised, convoluted and industrialised food system, we as consumers can and do have agency.

Vote with your fork

As Sara Roversi, founder and President of the Italian-based social enterprise Future Food Institute, states, “eating is an essential activity for human beings, but today it requires consciousness and awareness.” So perhaps eating more sustainably involves a mindset shift?

“Don’t underestimate the power of your informed questioning,” says Holden who encourages curiosity. “Highlight to retailers and manufacturers that you really care.” So whether we buy food from the supermarket or a farm shop, we can start by considering how something was produced or processed, who grew it, where it’s from and how it was transported, whether it’s actually in season.

“If you can’t get anything with a story you like, go to the customer service desk or write to them and say, I want locally-produced, sustainably-produced, in-season products, and they’ll listen,” says Holden. “If you can only afford to buy some of your fresh vegetables for instance from a box scheme or a farmers’ market, OK, that’s a huge step,” he adds. “If everybody in the country just even did 5% of their purchasing in a better direction that will change the system because in the end it’s us. We’re the powerful ones, not supermarkets. They’re only powerful as long as we’re passive. If we become active, if we become agents of change, they’ll listen because they’ll go out of business if they don’t.”

In the current food landscape, decision-making is tricky. Depending on personal preferences, should we opt for organic veg wrapped in plastic or non-organic plastic-free produce? Should we choose homegrown tomatoes grown out of season in energy-intensive polytunnels or tomatoes that have been grown in warmer climes then transported by truck from the continent? Actually, although the answer is not always straightforward, likely the latter thanks to the Spanish sunshine.

We’re the people who eat the food and elect the politicians. If you go to Westminster today and ask the government or the opposition how important is all this stuff, they’ll say, ‘oh, not very important’. Well, we have to prove them wrong.

Patrick Holden, CEO, The Sustainable Food Trust

Food production is responsible for an astonishing one-quarter (26%) of the world’s greenhouse gas emissions, from supply chain logistics to crop production, land use and livestock farming. Perhaps surprisingly, stats show that eating local doesn’t always translate to low carbon, because transport only contributes to a small part of most food’s overall emissions. What you eat has more influence. Foods with the highest greenhouse gas emissions across their supply chains include beef, lamb and cheese, while emissions from plants such as nuts, citrus fruits, apples and root veg are tiny by comparison.

Dr Chris Bryant, a Social Scientist and sustainable food expert at the University of Bath confirms that consumer dilemmas about aspects such as plastic packaging or food miles aren’t as important as the environmental impacts that occur before food leaves the farm gate, adds. “Thinking about animal product alternatives like plant-based meat, for example, it is far better for the environment to eat plant-based meat imported from America compared to eating cows reared in the UK,” he says.

The plant paradox

Adopting more plant-based diets would slash the food system’s environmental footprint, according to Bryant, while improving food security by reducing the amount of land needed to produce our food. “In the UK, we currently import vast amounts of crops to feed livestock animals, and this not only makes us reliant on food imports from other countries, it also increases the environmental impact massively,” he says. There are health benefits too. Bryant adds that “choosing a plant-based diet over a diet containing animal products will tend to mean more consumption of fibre and vitamins, and less consumption of cholesterol and saturated fat. The evidence overwhelmingly supports the view that plant-based diets are associated with lower risk of heart disease, cancer, diabetes, and obesity.

Bryant argues that energy is inevitably wasted during any meat production, because put very simply, animals are higher up the food chain and need to be fed by other plants or animals, unlike plants. “The vast majority of calories consumed by a chicken are not spent growing chicken breasts and thighs, but on heating the body, growing bones, and a range of other expenditures which are not at all useful to humans. Eating animals is always going to be an inefficient use of calories,” he says.

But Holden argues that it’s not as simple as eating less meat and more plants. He mentions the renaissance in heritage crops that increase genetic variation, adaptability and climate resilience. But not all plants are sustainable. “There are lots of unsustainably-produced plant materials [such as palm oil], plant components of our diet which, actually, we need to eat less of or even give up eating because they come from intensive plant production systems often from the other side of the world which are part of the problem.”

“It’s exactly the same with animals,” he says. “We need to differentiate between the animals and the plants which could and will form part of a sustainable farming system and those which are absolutely part of the problem and eat accordingly.”

In the UK, we currently import vast amounts of crops to feed livestock animals, and this not only makes us reliant on food imports from other countries, it also increases the environmental impact massively.

Chris Bryant, Director, Bryant Research

So, if you do eat meat, how much meat is sustainable? The Sustainable Food Trust’s Feeding Britain From the Ground Up 2022 study modelled a nation that switched to farming regeneratively ‘within planetary boundaries’. It found that current levels of food production could be maintained if we wasted less and ate a more sustainable diet. While some exotic crops such as tea, coffee and bananas, wouldn’t ever be grown here, Holden explains that most people should be basing their diet on regionally or nationally-sourced staple foods. “We’d have plenty of in-season vegetables and fruits, and enough grain to feed ourselves, but we wouldn’t have enough grain to feed intensive chickens, pigs and dairy cows. So that has huge dietary implications. It means no more cheap chicken, no more cheap pork from intensive pig systems, and no more dairy from mega dairies that feeds a lot of grains.

A sustainable agricultural transition would involve more mixed farming, says Holden. That includes more crop rotation of nitrogen-fixing crops to build richer soils and grass-fed sheep, beef and dairy cows on that land to ruminate and convert those crops into food. But what about the methane emissions? Holden explains that ‘old carbon’ already exists in the carbon cycle and it’s offset by the gain in soil organic matter. He grazes livestock on his 300-acre farm, the first in Wales to be certified organic. A recent audit found his system to be carbon negative: “It’s not just grass and clover that grows, we’ve got a dandelion festival going on here right now – the cows love them, they’ve got deep tap roots and they bring minerals up from the subsoil.” This holistic philosophy forms a central part of building a regenerative farming system, explains Holden. “Actually, the only way you can reliably build soil fertility at scale is with grazing animals. Paradoxically, now we actually need to eat the right kind of meat to help the transition.

Eco-labelling to eat more sustainably

Transparency is hard to come by. Denmark has proposed eco-labelling on foods to make their carbon footprint transparent to consumers. The Netherlands is looking into this option, and the UK Government is being urged by Tetra Pak and other businesses and organisations to implement environmental food labels. But Holden says that the truth is that it’s currently very difficult to go into a British supermarket and buy food, especially vegetables, that are part of the solution. That’s down to the fact that most supermarket food is sourced from intensive, extractive and polluting farming systems, he says, but also that the labelling currently in use doesn’t help consumers. “You just can’t tell [whether food is sustainable] so we need a new way of measuring on the farm and we need a labelling system which reflects the sustainable impacts of each farming system.”

That’s why the Sustainable Food Trust has been working for eight years on developing a Global Farm Metric, that Holden hopes will one day become an international standard. It’s based on the concept of ‘true cost accounting’ which accurately measures the hidden negative and positive impacts of food production. By quantifying everything from microbial diversity in the soil to workers’ rights, the framework assesses the social, economic and environmental sustainability of both regenerative and industrialised farming systems in an evidence-based way. Holden explains that big corporations and multinational supermarket chains are showing ‘huge interest’ in using this metric, “because they know their own customers want to know this information”.

The social and health impact of a sustainable diet

A key part of knowing the story behind the food you eat involves understanding who grew or reared it – how were the farmers or producers treated, paid and supported? Is that food supply chain inclusive, equitable and regenerative? From cotton and tea to cocoa and coffee, more than 1.9 million farmers and workers across more than 71 countries are part of the growing Fairtrade movement, and both the Fairtrade label and B Corp certification – a rigorous measure of a company’s social and environmental impact – indicate that brands take this social responsibility really seriously.

Eating is an essential activity for human beings, but today it requires consciousness and awareness.

Sara Roversi, President, Future Food Institute

Informational measures including carbon labels and animal welfare labels can inform people about how to eat more sustainably, says Bryant, who outlines some of the ways policy could make sustainable diets more mainstream. Financial measures like taxes and subsidies can encourage people to eat fewer animal foods and more plant-based foods, he explains. ‘Command and control’ measures could also impose limits on food production and consumption: “For example, minimum standards for animal welfare, or limiting the meat and animal products served in public catering,” explains Bryant. And finally, governments can implement ‘nudges’ to encourage people to choose more sustainable options: “For example, presenting plant-based foods as the default, positioning them first in buffet settings, and having them make up a higher proportion of menus in public catering will all encourage people to cut their meat consumption,” he says.

Improving national dietary guidelines is a key step too, because replacing highly processed foods with nutritious, sustainable diets has knock on effects for the health of entire nations if successful. To some extent, it’s a human rights issue, especially as climate change impacts exacerbate food insecurity. There’s huge potential for the Mediterranean diet to be positioned as a sustainable diet model, with benefits for people’s health and nutrition as well as positive environmental impacts. A recent Israeli study concluded that both the Mediterranean and the EAT-Lancet dietary patterns should be included in national dietary guidelines for both public health and sustainability reasons.

But none of this will happen without harnessing consumer power, says Holden: “We’re the people who eat the food and elect the politicians. If you go to Westminster today and ask the government or the opposition how important is all this stuff, they’ll say, ‘oh, not very important’. Well, we have to prove them wrong.

10 ways to eat a healthy, low-impact sustainable diet

  • Introduce more plant-based diversity into your diet, including plenty of wholegrains, legumes and field-grown veg that are less prone to spoilage (and won’t have to be air freighted).
  • If you eat meat, eat grass-fed meat in moderate quantities with a nose-to-tail philosophy.
  • Eat dairy and eggs in moderate quantities.
  • Eat small amounts of seafood from certified fisheries, taking stocks and capture method into consideration.
  • Opt for food produced using farming methods that minimise the use of antibiotics, hormones and toxic chemical inputs in food production.
  • Limit your consumption of foods high in fat, sugar or salt, and low in micronutrients.
  • Cook with more oils and fats rich in omega 3 such as olive and rapeseed.
  • Drink tap water instead of other soft drinks.
  • Minimise the use of plastic food packaging.
  • Discover creative ways to waste less food.

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