Sept. 14 (UPI) — Metropolitan regions in the Midwest and Pacific Northwest could grow all of their food locally — within 155 miles — according to a new study.
The analysis, which looked at how population, geography and diet would impact the localization of the American food supply, showed most Northeastern cities would still need to bring in food from farther afield to feed their residents.
For the study, published Monday in the journal Environmental Science and Technology, researchers looked at whether different sized cities had access to enough farmland to grow sufficient quantities of food.
Building on earlier research into the composition of diets, scientists calculated the resource demands of seven different diets, ranging from vegan to the meat-heavy diet typical of modern Americans.
“We had a list of the quantities of foods a person needs to eat to feed them for one year on a given diet,” senior study author Christian Peters told UPI in an email. “The next step in the process was to calculate the land requirements for supplying these foods.”
Peters is an associate professor at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University.
“We considered losses and waste, the feed needs of livestock and the average yields of crops in the United States. This enabled us to tally up the land requirements for each diet according to average U.S. crop yields,” Peters said. “The foodshed model then recalibrated these land requirements for each locality based on the relative productivity of the land in each county.”
The models showed that reducing meat consumption — from five ounces to 2.5 ounces per day — increased the potential for food supply localization. Replacing meat with plant-based protein, such as lentils, beans and nuts, could also offer a variety of health benefits, researchers suggest.
But the data showed eaters in the U.S. wouldn’t need to give up meat to localize their food supply. If meat portions were simply reduced, a lot more meat could be raised and processed much closer to the point of consumption.
“I was surprised by how much foods reliant on perennial and grazing land could be localized if the U.S. transitioned to a low-meat diet,” co-author Julie Kurtz told UPI in an email.
“The finding highlights the importance of considering land type,” said Kurtz, who was a student at the Friedman school at the time of the study.
Even if residents adopted a meat-free diet, cities such as New York, Boston and Miami would still need to import non-local food to meet demand. Still, the data showed total food supply localization is within the realm of possibility for larger swaths of the U.S.
“I was surprised just how local food could be,” Peters said. “I would have expected the foodsheds of large cities to be even larger than we observed. In retrospect, however, the results made sense to me because of the large agricultural land base of the U.S.”
Under all seven diets, researchers found food localization would leave the United States with a surplus of land for agriculture. Currently, a sizable portion of farmland is used to grow export crops and crops for biofuels.
Efforts to localize the American food supply would likely force consumers, policy makers and other stakeholders to grapple with difficult decisions over local land use priorities.
One of the unanswered questions posed by the latest study, and one that researchers and policy makers must wrestle with moving forward, is what do with “surplus” land.
“As demonstrated in the paper, none of the diets required all the productive capacity of the U.S.,” Peters said. “Right now, much of that productive capacity goes to growing export crops and biofuels along with an assortment of other non-food crops.”
“How does the picture for local and regional food look once those uses are included in the model?” Peters said. “And, what might be gained by using some of that land for conservation purposes?”