Food rating systems that take both sustainability and nutritional value into account could help grocery shoppers 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 items sold in the UK and Ireland.
The gigantic study, published August 8 in Proceedings of the National Academy of Sciences1, is among the first to estimate the environmental impact of products made with multiple ingredients, rather than just 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 generally good for the other,” says Clark. “You don’t have to make a decision that is good for the environment but could have a negative impact on your health.”
Source: Ref. 1.
Food production is one of the main contributors to climate change. A 2020 study found that even if emissions from burning fossil fuels were to end immediately, current trends in food systems could derail efforts to limit global warming to 2°C above pre-industrial levels.two.
Some foods, like red meat, produce far more greenhouse gases than others. Last year, a UK government survey found that more than half of people in the country want to make more sustainable choices around food. But because many foods contain multiple ingredients, it can be difficult to tease out the environmental impact of one product over another, says Clark.
“We have information on the environmental impacts of raw materials such as wheat and soybeans,” he says. But, “if you’re walking into your local grocery store, you’re not just buying wheat.”
To create a rating system that people would find easy to understand, 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 gave the foods an environmental impact score of 100, with 100 being the worst, by combining the impacts of the ingredients in 100 grams of each product. They considered various factors, including greenhouse gas emissions and land use.
The team found that products containing lamb and beef, such as prepared meat pies, had the most severe environmental impact, scoring up to three times higher than products made from poultry. The lowest-impact foods tended to be made from plants and included bread products, fruits, vegetables, grains, and high-sugar beverages.
Comparing the environmental impact score with nutritional information, the researchers found that healthier foods tended to have a lower environmental impact (see ‘Food for Thought’). There were some notable exceptions: both nuts and shellfish had good nutritional scores but relatively high environmental impacts.
If made more user-friendly and widely accessible, food classification systems like this one could help people make informed decisions about what they eat, says Olivier Jolliet, a specialist in quantitative and environmental health at the Technical University of Denmark in Kongens Lyngby. .
“There are big differences between foods, and we can start to make choices that actually improve our health and the environment in substantial ways,” he says. “This type of study can help us find our way there.”
