Many of the most nutritious foods are also the most sustainable


While it is relatively straightforward to compare the environmental footprint of producing apples versus oranges (or even beef), these calculations become much more complicated when the food contains multiple ingredients, and these make up the majority of what is sold at a typical grocery store. Until now, there have been no good methods to determine the impact of these foods, but an Oxford team recently published some of the first work to develop a sustainability metric for everything (edible) that can be found in your local grocery store.

Beyond the approach’s sustainability estimates, the Oxford team cross-referenced their results with the standard nutritional metric NutriScore. With this, they found that there were many “winners” where the food was both sustainable and nutritious, although there were some notable exceptions. And while the results weren’t too surprising, this method offers a new metric for consumers, retailers, and producers to make more informed decisions.

Secret recipes

One of the biggest obstacles to calculating the sustainability of multi-ingredient foods is that producers are rarely required to list the amount of each ingredient they put in a product. Quite the contrary: these details are often closely guarded trade secrets.

But in some countries, such as Ireland and the UK, at least some of this information is publicly accessible: the percentages of certain key ingredients. Researchers from the Livestock, Environment and People Program (LEAP) and Oxford Population Health at the University of Oxford used these details (from the FooDB resource) to estimate percentages of ingredients in similar products, including more than 57,000 food products representing almost all food and drink in UK and Irish supermarkets.

Once they had estimates of the ingredients, they used the environmental database HESTIA to calculate the impact of the entire inventory. The team calculated an environmental score for each food that included a combined metric of four main impacts: greenhouse gas emissions, land use, water stress, and the potential to cause toxic algal blooms in the masses. ‘downstream water (ie eutrophication potential).

As a final step, they cross-referenced their sustainability results with the commonly used nutrition metric called NutriScore. This ranks foods based on ‘good’ nutrients such as protein, fibre, fruit/vegetable content and healthy oils, as well as ‘bad’ nutrients such as calories, fat, salt and added sugar.

“We use NutriScore because it is used quite widely in many countries around the world and many researchers are familiar with the concept behind it,” said first author Michael Clark, from the University of Oxford. “The whole premise was developed to be applied at the population level to get better health outcomes. It’s gone through a lot of validation and testing, and at the population level, it’s been very effective at that.”

win-win

When the researchers tested their method on products with known ingredients, they found it worked well. The resulting sustainability rankings were also largely consistent with what would be expected given the main ingredients of any given item.

“Our findings were not very surprising,” Clark said. “For at least the last decade, there has been a growing body of evidence that certain commodities have a high impact, typically beef and sheep, and some commodities have a low impact, such as foods of plant origin (with some exceptions such as chocolate and coffee). ).”

In general, meat, cheese and fish, and anything made with these ingredients, had the highest estimated impacts. Anything based on fruits, grains or vegetables ranked lowest, as expected. When combined with NutriScore, there were clear products for everyone that were nutritious and good for the environment, such as whole grain foods and products. Chips also performed well due to their high “vegetable” content. Other foods, such as nuts, fish and meat, were nutritious, but relatively harder on the environment.

Work in progress

The research team hopes that their work will be a starting point for a metric that could be used by consumers, producers and retailers to make more sustainable decisions. Going forward, the biggest obstacle will remain the lack of ingredient transparency, which is unlikely to improve in the near future. Where and how the ingredients are produced is another factor that can change the impact considerably, and is rarely disclosed.

“We hope this is the start of a longer journey and an opportunity to work together to develop something that will be beneficial to all of us,” Clark said. “The most exciting part is the application: we now have a mechanism to enable comparisons between a bunch of food products that people produce, sell or buy, and this allows them to make informed decisions about the impacts of those choices.”

PNAS, 2022. DOI: 10.1073/pnas.2120584119

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