Sales of local foods make up a $20 billion industry today, according to a USA Today report. But “local” is so undefined that this could mean that a food that is state-approved as local is produce from a neighbor’s farm and sold at a farmers market. Or it simply could be manufactured in the state with ingredients from across the nation — or world. And whether or not that local food is more sustainable, economic, environmental, or healthier than its global (or “corporate”) counterpart is just as dubious. In fact, the consensus from experts tends to be: “It depends.”

But there also is consensus that neither completely replaces or is better than the other. As Auburn University Assistant Professor Daniel Wells said, “I don’t want to say it’s either global or local. I don’t believe that. It’s both.”

ENVIRONMENTAL. Is local food more environmental? “It’s difficult to generalize,” said North Carolina State University Assistant Professor and Local Foods Extension Specialist Dara Bloom. “It depends on how the food is grown, raised, caught, distributed ...”

For example, there is research that shows that non-local food travels 1,400-1,500 miles to reach your plate. But transportation is only about 11% of greenhouse gas emissions in agriculture. And, when one considers economies of scale, large-scale transportation going a long distance can be more efficient than a partially filled farm truck going to a farmers market.

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Auburn University Professor and Food Systems Institute Director Christy Bratcher sees local and global foods as being fairly equilaterally environmental. “From an environmental standpoint, my honest opinion is that what we’re doing on a conventional agriculture basis is safe for the environment and long-term sustainability,” Bratcher said. “From a local standpoint, it’s not unsafe, but we can’t grow enough food.

“Either way, we are doing things right environmentally ... but both also have people who are doing things that aren’t safe.”

SUSTAINABILITY. Comparing sustainability of the two can be just as iffy. “Is sustainability keeping grass green or providing food that lasts a lifetime?”

Bratcher asked. Citing the 2015 Trends in U.S. Local and Regional Food Systems report to Congress

, Bloom noted that farmers who sell locally, directly to consumers, often tend to use fewer pesticides and incorporate more sustainable practices … but conventional producers may have more land in conservation and use no-till practices.

Local production can mean growing in a greenhouse as well as an open field. Specializing in greenhouse vegetable production in his research, Wells said there is an argument to be made that greenhouse vegetables can be more environmentally sustainable because less water can be used, carbon emissions are greatly reduced, the produce can be higher in nutrients and vitamins, and it is not susceptible to environmental issues such as run-off. But, he added, “There is a trade-off. Greenhouses have higher energy requirements, so even if they don’t ship the produce, there is energy consumption.”

And, he said, “We can’t feed the world from greenhouses.” The only way to really feed the world is with the growth of staple field crops, such as grains, potatoes, wheat, and soy. Even the U.S. cannot be fed solely from local food as it stands now, he added. In a relatively free market, systems will emerge to most productively feed its people. “What has emerged is fairly large farms in centralized locations because it’s the least expensive option,” he said.

But greenhouses and technology such as hydroponics and aquaponics have a role to play as they can address issues of seasonality and efficiency, and can be put in the middle of Manhattan or in a rural area, he said.

AVAILABILITY. Another aspect of the debate between local and global is geographic availability. “I’ve heard it said — and I believe it, too — that Americans want to be able to choose what they want when they want it,” Wells said. But it’s a fairly obvious fact that everything Americans want can’t always be grown in their local environments.

“We have to be realistic about the demands there are for food and the education we are giving our kids. If we want local, we have to know how to cook what’s available,” Bratcher said. “Our grandparents had a whole art of food preservation, but it’s a lost art. We need to continue learning how to use local foods.”

While greenhouse crops are less subject to limitations on either, there are seasonality and site issues. For example, while it may seem counterintuitive, both lettuce and tomatoes are difficult, if not impossible, to grow in greenhouses in the summer, particularly in the South, Wells said. “So if you want specialty food every week, the current global scale is what will have to continue.”

“A lot of people want to use local food projects to address low-income food-access issues and support small and mid-size farmers,” Bloom said. That can work, but would require engaging the larger food system’s economy of scale to provide a lower price or attaining a subsidy with external funding.

ECONOMICS. But even the economics of local food production and purchase can go either way. Local food purchases tend to have a spill-over effect into the community that is generally positive, Bloom said. “Farmers who promote themselves as local tend to use local employees and suppliers.” Additionally, businesses that are near local farm markets tend to reap the benefits.

Local production means paying wages to local people, Bratcher added. “You are keeping jobs close to home which is great.” But, you also will likely pay more for those products because it’s kind of a “boutique” style of selling, she said. “Some people can afford that, but not everyone.”

There also could be repercussions on other local businesses, Bloom said, explaining, “What I’m spending at a farmers market, I’m not spending at the local grocer’s, or I’m cutting out the middle man who also could be local.”

Recent research has shown that the farmers who sell local produce and are profitable are generally not the ones selling direct to consumers, e.g., at farmers markets, Bloom said. Rather, the most profit is generally attained by distributing local goods through intermediated markets, such as retailers, distributors, food hubs, etc. But that can defeat a purpose of local.

An early hallmark of local food systems was farmers talking to customers as people turned to local to fulfill certain values, she said, but that is more challenging when one is selling to a larger market because it’s an intermediated relationship.

It also can be difficult for local producers to get their products to market, Bratcher said. They have a hard time assuring distributors that they can provide specific amounts, and even when they can assure quantity, “Who do you talk to to get in the door?” she asked.

HEALTHFULNESS. “Food is food, no matter the production system,” Bratcher said. Whether talking tomatoes, strawberries, or beef, each food has specifications as set by the USDA Food Composition Database — whether grown locally or even in a foreign country. Additionally, she said, “If you want heart-healthy omega acids, you’d have to eat so much beef there would be other issues.”

Advocates of local foods often focus on freshness as increasing their nutritional value. There is some accuracy in this, as “local and fresher go hand in hand,” Wells said. The more quickly produce is consumed after harvest, the more healthful and tasty it will be. However, the maintenance of a cold chain from farm to table also can have significant impact on both vitamin and taste retention.

Although there is research showing an association between those who buy local food and good health, the research does not establish causality, Bloom said. That is, it could be that healthier people tend to prefer shopping at farmers markets rather than that eating local makes them healthier.

But it is seen that people who are involved in community gardens tend to eat more fruits and vegetables and be more involved in the community, Bloom said. And such involvement brings people together around the table and helps in the understanding of where their food comes from.

THE FINAL WORD. The bigger message is that, Bloom said, “There’s no one definition of local, so none of the positive benefits are guaranteed. But if we understand what your community is seeking, we (the local foods extension specialists) can work with them.”

“I think we could be doing people a disservice if we harp on local is always better. It’s misleading to pretend the local food movement is the be-all,” Wells said. “People want a water-tight argument for one way or another, but both address different issues, and both benefit the consumer.”

The author is Editor of QA magazine. She can be reached at llupo@gie.net.