If the entire population of the United States changed their diet from a beef-heavy plan to one based on chicken, it would be possible to feed 120 to 140 million more people with the same resources. (photo from wis-wander.weizmann.ac.il)
How much does a steak really cost? Or chicken nuggets, or a plate of hummus? New research by Prof. Ron Milo and Alon Shepon of the plant and environmental sciences department of the Weizmann Institute of Science, together with Prof. Gideon Eshel of Bard College in New York, took a look at the figures – including the environmental costs – of the different foods we eat. The research appeared in Environmental Research Letters.
The data for the study came from figures for cattle and poultry growing and consumption in the United States. To compare, the researchers calculated the nutritional value of each – usable calories and protein – versus the environmental cost. The latter included the use of land for fodder or grazing and the emission of greenhouse gases in both growing the food and in growing the animals themselves.
Chickens, according to the study, produce much more edible meat per kilogram of feed consumed, and they produce their meat faster than cattle, meaning more can be grown on the same amount of land. For every 100 calories and 100 grams of protein fed to beef cattle, the consumer ends up with around three calories and three grams of protein. For poultry, that figure is about 13 calories and 21 grams of protein.
The researchers then asked what would happen if the entire population of the United States were persuaded to change their diet from a beef-heavy plan to one based on chicken. Their answer: it would be possible to feed 40% more people – 120 to 140 million more people – with the same resources.
What would happen if the same population was persuaded to adopt an entirely plant-based diet? That is, instead of using land to grow cow or chicken feed and then eating the animals, to use that land to grow nutritional crops – mainly legumes, including peanuts, soya, garbanzos and lentils. These can supply all of a person’s nutritional requirements, except vitamin B12, which can be obtained from nutritional yeast.
A separate study, published in Environmental Science and Technology – “Environmentally optimal, nutritionally aware beef replacement plant-based diets,” by Milo, Shepon, Gidon Eshel and Elad Noor – suggests that an extra 190 million people could eat off the same environmental resources in this way.
“If we changed our diet, we would change the environmental price we pay, with every meal,” said Shepon. “Eating a plant-based diet can both meet our nutritional requirements and save on land use, as well as the release of greenhouse gases into the atmosphere and excess nitrogen from fertilizers into the water supply. These are real costs that we all bear, especially when people eat beef.”
Milo’s research is supported by the Leona M. and Harry B. Helmsley Charitable Trust; Dana and Yossie Hollander, Israel; and the Larson Charitable Foundation. Milo is the incumbent of the Charles and Louise Gartner Professorial Chair.
For more on the research being conducted at the Weizmann Institute, visit wis-wander.weizmann.ac.il.