Connor said the university expects some local or sustainably grown items will cost more but is convening a work group to address the issue, so that the cost is not passed on to students. In many cases, he said, Bon Appetit can buy directly from the farmer and cut out the cost of a middleman.

The Real Food Challenge is a national campaign that started six years ago. Berger, who is the Mid-Atlantic regional coordinator for the Real Food Challenge, said that though JHU is the first in the state to adopt the pledge, he is working with student groups on several other local campuses and hopes they will follow suit.

Johns Hopkins is "such a huge name in the health community," Berger said. "Endorsing the Real Food Calculator as the standard they get behind will have a ripple effect."

Tom Faison, a sophomore at Towson University and one of several students in the early stages of organizing a drive to get the university to sign the pledge, said much of the movement toward sustainable, local food has so far been on an "individual level." The change they want to see in society's farming and eating habits will come more quickly with the backing of major institutions, he said.

"A large institution with a very strong amount of buying power and capital influence is essentially the perfect tool to set a precedent," said Faison, a 19-year-old film and journalism major from Frederick.

Hopkins' decision will "hopefully put us on a faster timeline for success" in getting Towson to sign on, he said.

Supporters said there will be several challenges for JHU to get to the 35 percent mark in six years. The Mid-Atlantic growing season means it will be difficult to find locally sourced produce in the winter, though Connor said he thinks that the university could buy greater quantities of local produce in the spring, summer and fall to offset that problem.

"If we were a school in a more rural environment, in Florida or California, I think we'd have an easier commitment," said Connor, adding that Bon Appetit has a tomato supplier in Florida that pays their workers a living wage, which will help toward the goal.

Santo said there's also been pushback from some students who miss their junk food. Some want Oreos and Campbell's soup in a convenience store on campus that once offered those items but now is mostly stocked with organic food, she said.

But with climate change affecting agriculture in the U.S. and across the globe, and with eating habits changing, Santo said society needs to adapt.

"If we can't figure out better production systems, it's going to make everything else irrelevant," she said.