Healthier foods are better for the planet: new study

An analysis of 57,000 foods published in the Proceedings of the National Academy of Sciences (PNAS) “reveals which [foods] have the best and worst environmental impacts. A team of researchers used an algorithm to estimate how much of each ingredient was in thousands of products sold in major UK supermarket chains. The scientists then gave food items an environmental-impact score out of 100 — with 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.

Healthier foods tended to have low environmental impacts, the team found. Products containing lamb and beef — such as ready-made meat pies — had the most serious environmental impact. The lowest-impact foods tended to be made with plants and included bread products, fruits, vegetables, grains and sugar-rich drinks.” See ‘Food For Thought’ (Figure 1) below. “There were some notable exceptions: both nuts and seafood had a good nutrition score but relatively high environmental impacts.”

Figure 1. Food for Thought

Keep in mind that previously published analyses have shown there are varying environmental impacts of nuts and seafood, depending on the type of nut and seafood. In an article published in the American Journal of Clinical Nutrition (2022), Rose and colleagues found that substituting peanuts for almonds in self-selected diets in the U.S. reduced the water scarcity footprint by 30 percent. In the same study, replacing a serving of shrimp with cod reduced greenhouse gas emissions by 34 percent. However, while whitefish – such as cod – have a low climate impact, they are among the least nutrient-dense seafood. In contrast, wild-caught pink salmon and sockeye salmon, along with wild-caught, small pelagic fish (e.g., anchovies, mackerel, herring) and farmed bivalves (e.g., mussels, clams, oysters), are the best choices for nutrient-dense, low-emissions protein sources (Bianchi et al., 2022). Furthermore, a study by Dr. Jessica Gephart and colleagues published in Nature (2021) reported substantial differences in the amount (pounds) of CO2 equivalents by type of seafood (per serving) (See Figure 2 below). To learn more, see:

Figure 2. Fishing for greener seafood

Aim for seafood with low greenhouse gas emissions. Farmed fish have other costs such as nitrogen and phosphorus runoff, but they’re typically lower than that of chicken.

Photo: Source: Nature 597: 360, 2021.


Clark M, Springmann M, Rayner M, et al. Estimating the environmental impacts of 57,000 food products. Proc. Natl Acad. Sci. 119, e2120584119 (2022).

Kreir F. Healthier foods are better for the planet, mammoth study finds. Nature. August 10, 2022. Available at:,but%20relatively%20high%20environmental%20impacts.

Bianchi, M., Hallström, E., Parker, R.W.R. et al. Assessing seafood nutritional diversity together with climate impacts informs more comprehensive dietary advice. Commun Earth Environ 3, 188 (2022).

Gephart JA., Henriksson PJG, Parker RWR. et al. Environmental performance of blue foods. Nature 597,360–365 (2021).

Liebman B. Which seafood causes the least damage to the planet? It’s complicated. Center For Science in The Public Interest. March 28, 2022. Available at:

Rose D, Willits-Smith AM, Heller MC. Single-item substitutions can substantially reduce the carbon and water scarcity footprints of US diets. The American Journal of Clinical Nutrition 115(2), 378-387 (2022).

Published by greengrass50

My name is Christine McCullum-Gomez, PhD, RDN. I am a registered dietitian nutritionist with expertise in environmental nutrition, food and nutrition policy, food and nutrition security, food justice, chronic disease prevention, regenerative & organic agriculture, and sustainable healthy dietary patterns. Currently, I serve on the Editorial Review Board and as a Column Editor for the Journal of Hunger & Environmental Nutrition. I live in Bogota, Colombia with my husband, two teenagers (boy-girl twins), and our dog Honey. My website is: You can follow me on Instagram at:

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