In Our September/October 2016 Issue
Letter from the Publishers
Getting the Most Out of Available Agricultural Land
You might think that if a “plant based” diet is more sustainable than what most people in the U.S. now eat, that an all vegetarian or a vegan diet would be even more so. The less meat you eat the more sustainable the diet is, right? It’s not that simple, according to a recent article in Quartz about a study published in July in Elementa: Science of the Anthropocene. *
While eating fewer animal products increases the number of people who can be fed from existing farmland, eliminating animal products altogether by choosing a vegan diet is less effi cient than both a vegetarian diet that includes dairy (most eff cient in terms of people fed per acre), and a vegetarian diet that includes both eggs and dairy.
The reason is that there is a lot of land that can be used for animal agriculture that cannot be used to raise edible produce. The vegan diet was the only one that used only cultivated cropland and some grazing land, but no perennial cropland whatsoever.** (Seems like it should be grazing land that vegans don't use, but that's what it says.) Taking land out of production that is now used to make food means fewer people can be fed because the number of acres devoted to food production is less. In effect, land that can feed people is wasted.
In fact, omnivorous diets that include 20% and 40% animal products were ranked third and fourth respectively in number of people fed per acre—ahead of the vegan diet, which came in at fifth. If in the future we have to feed more people without devoting a lot more acreage to raising food, we’ll have to use all the land now being used for food production to maximum advantage.
Based on this study, it appears that animal agriculture must be part of the solution to “feeding the world.” But meat eaters should not rejoice. The study suggests that a 60% to 80% reduction in the amount of animal products produced in the U.S. would be needed to bring the U.S. up from dead last to just third or fourth on the efficiency scale. In fact, we would do better to go to a vegetarian diet that includes dairy (most efficient), or a vegetarian diet that includes both eggs and dairy (second most efficient).
One study settles nothing. But it is interesting because it contradicts a commonly held belief that a vegan diet is the most environmentally sustainable, at least if measured by the standard of people fed per acre. This study did not measure carbon footprint, though that is a related topic. It raises a question that we think is crucial: How will we measure the sustainability of our dietary choices going forward? We’ll be keeping a close eye on this.
** Carrying capacity of U.S. agricultural land: Ten diet scenarios,” published July 22 at Elementa.
** See study section 3.2 Land requirements of diet, “Perennial crop requirements were zero in the vegan diet.
-Riley Davenport and John Vawter, Publishers