It’s long been clear that reducing meat consumption is one way to enable our planet’s farmland to feed more people. Now, in the case of the United States, we have an idea of by just how much. In a first its kind study, published recently in the journal Elementa: Science of the Anthropocene, researchers took a full accounting of the food producing capacity of all the land in the contiguous U.S. and calculated how many people could be fed depending upon how much meat we eat.

They found that if we continue to eat the way we do, we can feed 130 percent of the U.S. population on current U.S. farmland. But lest that lull anyone into complacency, the researchers found that if we all were to go vegetarian, including consuming dairy, we could double the numbers of mouths fed.

For the study, researchers calculated the nutritional needs of Americans and the foods that fall into each of the required food groups. Then they calculated the land required to grow each of these foods. Finally, they calculated the carrying capacity of the land in the US, taking into account how much land is available for three different agricultural uses—food crops, grazing, and land for growing food for livestock. Researchers used these calculations to this to determine how much land is used and how many people are fed under different diet scenarios, with our current diet as a baseline.

The various omnivore scenarios included different percentages (100, 80, 60, 40 and 20) of the U.S. population consuming a diet that includes meat, with the remainder eating an ovo-lacto vegetarian diet. There were three wholly vegetarian scenarios: ovo-lacto, lacto, and vegan. With the exception of our current diet which exceeds dietary guidelines, all of the diet scenarios were equal in calories and met recommended dietary guidelines; what changed was the source of the protein.

When it comes to the footprint of agriculture, four of the diet shifts didn’t produce any changes, even while they increased the number of people fed. The scenarios in which 40 percent and 20 percent of the U.S. are omnivore and all three vegetarian diets shrank agriculture’s footprint, to varying degrees.

When it comes to mouths fed, if we all ate meat, but had a healthy diet that met dietary guidelines, we could feed 16 percent more people. Even a scenario in which 40 percent of the population consumes meat puts food in 87 percent more mouths. If we were all lacto-vegetarians, we could feed 101 percent more people.

But steering clear of all animal products didn’t have the impact some might expect. The vegan diet fed only 83 percent more people, somewhere between the gains of the 40 and 60 percent omnivore diet.

“One of the takeaways of this study is to beware of preconceived notions about the impact of certain diets,” says lead author Christian Peters. “The vegan diet did not feed the most people.”

But vegans can take solace in the fact that while their diet didn’t feed the most people, it has the tiniest footprint of all. —Catherine Elton | 29 July 2016

Source: Peters, Christian J. et al, (2016) Carrying capacity of U.S. agricultural land: Ten diet scenarios, Elementa: Science of the Anthropocene. doi: 10.12952/journal.elementa.000116

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