Many of the most nutritious foods are also the most sustainable

While it is relatively simple to compare the environmental footprint of apple production with that of oranges (or even beef), these calculations become much more complicated when foods contain multiple ingredients and these make up the majority of what is sold in a typical grocery store. There have been no good methods to determine the impact of such foods so far, but an Oxford team recently published some early work on developing a sustainability metric for everything (edible) that could be found at their grocer. local.

Beyond the sustainability estimates of the approach, the Oxford team continued to cross-reference its results with the NutriScore standard nutritional metric. With this, they found that there were many “win-win” foods where the foods were 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 manufacturers to make more informed choices.

Secret recipes

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

But in some countries, like Ireland and the UK, at least some of this information is publicly accessible – the percentages of some key ingredients. Researchers from the University of Oxford’s Livestock, Environment and People (LEAP) and Oxford Population Health program used these details (from the FooDB resource) to estimate the percentages of ingredients in similar products, including over 57,000 food products representing nearly all of the food and drink in British and Irish supermarkets.

Once they got the ingredient estimates, they used the HESTIA environmental database to calculate the impact of their 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 downstream water bodies (i.e. eutrophication potential). .

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

“We use NutriScore because it is used extensively in many countries around the world and many researchers are familiar with the concept behind it,” said lead author Michael Clark of the University of Oxford. “The whole premise was developed to be applied at the population level for better health outcomes. It has undergone a lot of validation and testing and, at the population level, it has been very effective at that.”

Win-win

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

“Our results weren’t very surprising,” Clark said. “At least in the last decade, there has been an increasing amount of evidence that some products have a high impact, typically beef and sheep, and some products have a low impact, such as plant-based foods (with some exceptions such as chocolate and coffee). “

Overall, meat, cheese and fish, and anything made with these ingredients, had the highest estimated impacts. Anything based on fruit, grains, or vegetables is ranked lower, as expected. When combined with NutriScore, there were clearly win-win products that were nutritious and good for the environment, such as whole foods and agricultural products. The fries also performed particularly well due to their high “vegetable” content. Other foods, such as nuts, fish, and meat, were nutritious but relatively more harmful to the environment.

Works in progress

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

“We hope this is the start of a longer journey and an opportunity to work together to develop something that is mutually beneficial,” said Clark. “The most interesting part is the application: we now have a mechanism to allow comparisons between a range of food products that people produce, sell or buy, and this allows them to make informed decisions about the impact of these choices.”

PNAS, 2022. DOI: 10.1073 / pnas.2120584119

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