When food advocates talk about “eating local,” the usual response is that it’s just not possible. Urban centers can’t support their own populations, the conventional wisdom goes, and so “locavorism” could never go mainstream.
But a new study from University of California Davis upends that thinking, finding that up to 90% of the US population could be fed a standard American diet consisting only of food grown and raised within 100 miles. Local food systems can have a number of positive impacts, including cutting the greenhouse gas emissions from transporting food long distances—especially when the foods are refrigerated or frozen—and supporting local economies and increasing food security.
The researchers at UC Davis considered a number of factors in designing their computer models and making their calculations, including what counts as local and the kinds of diets people actually eat. The authors recognized that in a locally sourced scenario, none of their diet models would exactly reflect the way people eat today, but they were designed to provide equivalent calories from all the food groups—grains, vegetables, fruit, meat, eggs, and dairy—as they are currently eaten.
The researchers pointed out that switching to an overwhelmingly local diet would require significant changes to storage systems, crop types, and other infrastructure, as well as shifts in preferences and prices.
Even with these limitations, though, the findings were surprisingly optimistic. While vegetarian diets are the most conducive to local eating, the standard American meat- and egg-reliant diet, and diets that are even more meat-intensive than that, could also be sustained for most people. (The meat-intensive diet uses three times as much cropland as the vegetarian diet; cropland was calculated based on conventional livestock practices, not grass-fed or other types.)
The researchers found that based on population data from the year 2000, up to 82% of people in the US could eat a standard American diet with food from within 50 miles of home. That proportion goes up to 85% for a vegetarian diet, and down to 80% for a meat-intensive diet. If the foodshed radius expands to 100 miles, the potential for a standard American diet goes up to 90%, 93% for a vegetarian diet, and 88% for a meat-intensive diet.
Not everyone can eat so locally, though, even in the utopian model created with the study’s computer programs and algorithms. While most cities, including Chicago and San Francisco, can feed 100% of their populations with food from within 50 miles, large cities that have relatively little nearby cropland cannot. ”New York City and Los Angeles, for example, can support only about 10% of their populations with a 50-mile foodshed radius but as much as 30-50% with a 100-mile foodshed radius.”
Just another reason to leave New York, guys.