In an analysis of 19 previous investigations involving millions of people, researchers at the University of Minnesota and Oxford University examined the human-health and environmental impacts of 15 different food groups, including legumes, nuts, fruits, vegetables, whole grains, red meat, dairy, eggs, fish and sugar-sweetened beverages. The foods were compared with one another based on how they influence the risk of disease and the toll they take on the planet in terms of water and land use, water and soil pollution, and greenhouse gas emissions.

The results, published in the Proceedings of the National Academy of Sciences, showed that, for the most part, foods that promote good health are also better for the planet—and the opposite is also true. For instance, the negative environmental impact of producing a serving of processed or unprocessed red meat is 10–100 times larger than that caused by producing a serving of vegetables, and the latter are also linked to a bigger reduction in disease and mortality risk. The study mentioned two notable exceptions: Sugar-sweetened beverages may be considered bad for health but do not have a sig­nificantly greater effect on the environment than vegetables or fruits, while eating fish may be good for health but is not as good for the planet as plant-based protein—from legumes, for example.

The takeaway message: If you want to tread more lightly on the environment and boost your own health at the same time, eating less meat and more plants is the way to go. And if you go with something like beef, chicken or fish, consider how those are sourced and raised. For instance, fish caught by trawlers in the open ocean will generally have a much higher environmental impact than catfish and rainbow trout raised in inland tanks.