Scientists identify the most environmentally harmful animal product in the American diet

animal products
CC BY 2.0 Marc Flores

A new paper compares eggs, dairy, poultry, beef and pork to determine which has the biggest environmental impact.

If you guessed beef, you’re right.

Yet another study has confirmed that beef is the most environmentally harmful animal product the American diet. Beef production uses the most water, land, and nitrogen fertilizer while producing more greenhouse gas when compared to pork, poultry or eggs in a per-calorie comparison. Even dairy was found to be less resource-inefficient when compared with beef.

The authors find that producing one calorie of beef uses 11 times more water and six times more nitrogen fertilizer than the other animal products. Poultry, pork, eggs and dairy were found to use relatively similar resource levels.

PNAS, "Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States"/via

According to the paper, about 40 percent of the total land area of the United States is currently dedicated to the production of animal-based products. That includes the land needed for pasture, as well as feed crops. Much of this land could instead be dedicated to crops that are directly consumable by humans, and would require fewer resources per calorie.

Interestingly, the authors make an argument against the idea that cattle ranching often occurs in arid parts of the West, which is unfit for most crops. They argue that these grasslands could provide other ecological benefits if they weren’t being farmed, particularly by enhancing biodiversity and creating wild habitats.

You may be wondering about eating fish—which can also have negative impacts on the environment. This paper did not analyze seafood for two reasons: a lack of comprehensive data and because sea food only accounts for 0.5 percent of the calories consumed by the average American.

This new analysis may help people make more informed choices when it comes to making purchasing decisions. While many of our readers opt to cut animal products out of their diets, this research makes it clear that not all meat has the same impact.

The authors also hope their findings can steer policy makers when it comes to farming and food security decisions. “Because our results reflect current US farm policies and agrotechnology, the picture can change markedly in response to changes in agricultural technology and practice, national policies, and personal choice,” they write.

The findings were published today by the Proceedings of the National Academy of Sciences. Researchers from a number of different institutions collaborated on the project: Gidon Eshel of Bard College, Alon Shepon and Ron Milo of the Weizmann Institute of Science in Israel, and Tamar Makov of Yale University.

Tags: Agriculture | Beef | Factory Farming

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