Saturday, October 1, 2022

Study revealed the environmental impact of processed foods

More nutritious foods are often more sustainable.

Understanding and communicating the environmental impacts of food products is key to enabling transitions to environmentally sustainable food systems. While previous analyses compared the impacts of food commodities such as fruits, wheat, and beef, most products contain numerous ingredients. 

However, because the amount of each ingredient in a product is often known only by the manufacturer, it has been challenging to assess their environmental impacts.

A new study estimated the environmental impact of 57,000 food products in the UK and Ireland. Scientists from the University of Oxford used a transparent and reproducible method to access the ecological impacts of multi-ingredient products. It offers a first step toward enabling consumers, retailers, and policymakers to make informed decisions on the environmental impacts of food and drink products.

Lead author Dr. Michael Clark says, “By estimating the environmental impact of food and drink products in a standardized way, we have taken a significant first step towards providing information that could enable informed decision-making. We still need to find how best effectively to communicate this information to shift behavior towards more sustainable outcomes, but assessing the impact of products is an important step forward.”

More than half of UK consumers want to adopt more environmentally responsible food choices, according to a report by the Food Standards Agency*, and food companies are simultaneously establishing aggressive net zero greenhouse emission targets. However, there is a shortage of comprehensive environmental impact data on food and beverage items, which would enable customers and businesses to make more sustainable decisions.

For the study, scientists used publicly available information to derive estimates of the environmental impact of 57,000 food products. They examined greenhouse gas emissions, land use, water stress, and the possibility for eutrophication, which occurs when water bodies become enriched with nutrients, frequently leading to destructive algal blooms and eventually causing the death of other life. The team integrated these four scores into a single projected composite environmental effect score per 100g of product for analysis, visualization, and communication reasons.

Professor Peter Scarborough, Oxford Professor of Population Health, says, “This work is very exciting. For the first time, we have a transparent and comparable method for assessing the environmental footprint of multi-ingredient processed foods. These foods make up most of the supermarket shopping we do, but until now, there was no way of directly comparing their impact on the environment.”

“This work could support tools that help consumers make more environmentally sustainable food purchasing decisions. More importantly, it could prompt retailers and food manufacturers to reduce the environmental impact of the food supply, thereby making it easier for all of us to have healthier, more sustainable diets.”

Scientists quantified the differences in environmental impact between multi-ingredient products. They found those made of fruits, vegetables, sugar, and flour, such as soups, salads, bread, and many breakfast cereals, have low impact scores, and those made of meat, fish, and cheese are at the high end of the scale. Jerky, biltong, and other dried beef products, which typically have more than 100g of fresh meat per 100g of the final product, often have the highest environmental impact.

Scientists discovered significant heterogeneity within particular food categories, including meat and meat substitutes, lasagne, cookies and biscuits, and pesto sauces. The environmental impact of lower-impact items for various food kinds was frequently half to a tenth that of higher-impact ones. If shared with customers and retailers, this information could encourage consumers to choose sustainable foods without making significant dietary changes, like switching from beef to beans.

More sustainable products tended to be more nutritious, including meat and meat substitutes, when comparing the environmental effect score to their nutritional content as determined by the Nutri-score technique. There are certain exceptions to this tendency, such as sugary beverages, which are not only nutritionally inferior but also have a minimal influence on the environment.

Jennie Macdiarmid, Professor of Sustainable Nutrition and Health at the Rowett Institute, University of Aberdeen, says, “An important aspect of the study was linking the environmental impacts of composite foods with the nutritional quality, showing some of the synergies and trade-offs between different parameters. Using this new method, manufacturers can reduce the environmental impact while ensuring a high nutritional quality of products.”

The amount of every ingredient in a multi-ingredient food or drink product is usually known only to the manufacturer. Still, in the UK, they are legally obliged to provide percentage values for certain ingredients, and ingredients are listed on the packaging in order of size.

Using known percentages and order of ingredients, scientists inferred unknown values, cross-referencing products and components using a large dataset of products. Individual ingredients were mapped to environmental databases, and the percentages of all ingredients within each product were used to estimate the impact of each whole product.

Scientists also used foodDB – a Big Data research platform at Oxford, which collects and processes data daily on all food and drink products available in 12 online supermarkets in the UK and Ireland, and a comprehensive review of 570 studies of the environmental impact of food production, including data from 38,000 farms in 119 countries.

Dr. Richie Harrington, head of foodDB, says“Our method fills an information gap on the environmental impacts of multi-ingredient foods. The algorithms we developed can estimate the percentage contribution of each ingredient within a product and match those ingredients to existing environmental impact databases. Applying this methodology to generate impact scores for large numbers of products, we illustrated how this can be used to derive quantifiable insight on the sustainability of those products and their relationship to their nutritional quality.”

Journal Reference:

  1. Michael Clark, Marco Springmann, et al. Estimating the environmental impacts of 57,000 food products. PNAS August 8, 2022. DOI: 10.1073/pnas.212058411
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