Healthier foods are better for the planet, mammoth study finds


Food rating systems that consider both sustainability and nutritional value could allow grocers to make informed choices.Credit: Matthew Horwood/Getty

Healthier and more nutritious foods tend to be more sustainable and environmentally friendly than those with low nutritional value, according to an analysis of more than 57,000 food products sold in the UK and Ireland.

The mammoth study, published August 8 in Proceedings of the National Academy of Sciences1, is one of the first to estimate the environmental impact of products made from multiple ingredients, rather than individual foods. This information could help consumers understand how items compare in terms of nutrition and sustainability, says co-author Michael Clark, an environmental scientist at the University of Oxford, UK.

“What’s good for one is usually good for another,” Clark says. “You don’t have to make a choice that’s good for the environment but could have a negative impact on your health.”

Food for thought: scatter plot comparing environmental impact and nutritional impact of a range of foods.

Source: Ref 1.

Food production is a major contributor to climate change. A 2020 study found that even if emissions from burning fossil fuels cease immediately, current trends in food systems could derail efforts to limit global warming to 2°C above pre-industrial levels.2.

Some foods, like red meat, produce far more greenhouse gases than others. Last year a UK government investigation found that more than half of people in the country want to make more sustainable food choices. But because many food products contain multiple ingredients, it can be difficult to disentangle the environmental impact of one product from another, Clark says.

“We have information on the environmental impacts of products like wheat and soy,” he says. But “if you walk into your local grocery store, you’re not just buying wheat.”

To create an easy-to-understand scoring system, Clark and his colleagues used an algorithm to estimate the amount of each ingredient in thousands of products sold in major UK supermarket chains. The researchers then assigned the foods an environmental impact score out of 100 – 100 being the worst – by combining the impacts of the ingredients in 100 grams of each product. They considered several factors, including greenhouse gas emissions and land use.

The team found that products containing lamb and beef – such as ready-to-eat meat pies – had the most severe environmental impact, reaching up to three times more than products with poultry base. Low-impact foods were generally made from plants and included baked goods, fruits, vegetables, grains, and high-sugar drinks.

By comparing the Environmental Impact Score with nutritional information, researchers found that healthier foods tended to have lower environmental impacts (see “Food for Thought”). There were some notable exceptions: nuts and seafood had a good nutritional score but relatively high environmental impacts.

If made more user-friendly and widely accessible, food rating systems like this could help people make informed choices about what they eat, says Olivier Jolliet, quantitative and environmental health specialist at the Technical University of Denmark in Kongens Lyngby. .

“There are big differences between foods, and we can start making choices that really improve our health and our environment in substantial ways,” he says. “This type of study can help us find our way.”

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