From factories and farms half a world away to that first cilantro-sprinkled bite, ingredients for a typical taco collectively travel 2.6 times the circumference of the earth to reach your local taco truck.

That’s the conclusion of a design and architecture class at California College of the Arts after months of research.

“It really reconfigures the idea of the Mission taco,” said Alison Sant, a founder of the Studio for Urban Projects, where she recently introduced a presentation by the class.

Taught by landscape architect David Fletcher and members of the design collaborative Rebar, the class set out to map the foodshed of a nearby taco truck, following each ingredient from conception to waste.

The result was a “richly complex network of systems, flows and ecologies” that the class termed the “global Tacoshed.” Exploring the theme of “a holistic and sustainable urban future,” the class challenges the popular notion that growing and buying locally grown foods is always the most environmentally sound choice. While it seems counterintuitive, Fletcher and his students suggest that moving food products from one continent to another can, in certain cases, save more energy than growing food locally.

Over the fall semester, the class tracked the origin and destiny of each element in the production of a taco from Juan’s Taco Truck, generally found at the corner of 17th and Carolina streets in Potrero Hill. Each student chose an individual ingredient to follow, from the adobo seasoning to the aluminum foil wrapping and propane used in cooking.

“It was very difficult to trace the origins of these foods,” said John Bela, a director at Rebar and an instructor for the class. “There was an intentional obfuscation of food origins that we didn’t anticipate. We were stonewalled by corporations. So we had to use subterfuge, like having our Puerto Rican aunt call to ask.”

While the cosmically-oriented and locally-sourced Mexican restaurant Gracias Madre turns to its nearby biodynamic farm for ingredients, and local, seasonal produce inspires menus at Bar Tartine and Weird Fish among others, the locavore movement has yet to seep into our neighborhood’s traditional taquerias and taco trucks.

For Juan, price remains the primary criteria when ordering ingredients for his taco truck. Customers and managers at Mission taquerias agree. Like Juan, most order the bulk of their supplies from national or regional distributors such as Costco and Restaurant Depot.

Esquivel Santana, owner of Tacos San Buena and two El Tonayense taco trucks, said he had no idea where his food comes from beyond its street-side delivery. “I think maybe they have an office in Omaha, maybe that’s where they get their products,” he hazarded.

“If we order local produce,” he added, “it means more expensive tacos,” as customers at Gracias Madre can attest.

Rachael Yu, one of the students involved, said that Juan is simply looking for “the cheapest taco you can produce.”

Some of the class’s findings:

– Avocados come from a farm in Chile with an annual profit of $360 million and are shipped to         “value-added depots” in the United States that inspect each fruit with an acoustic firmness             sensor.

– Pinto beans are sent from the largest edible bean company in the U.S., first shipped from farms     around the country to a processor in Denver, Colorado.

– Sour cream comes predominantly from dairy farms in the Chino Valley outside of Los Angeles.

– Iceberg lettuce, with a shelf-life of 15 days, is rushed from the fields of Guadalupe, California.

– Salt travels the shortest distance from salt production ponds in South San Francisco Bay.

– Aluminum foil made from bauxite mined in Australia travels 17,500 miles. But aluminum can be     recycled indefinitely without degrading in quality if customers take the time to deposit the               wrappers in recycling bins.

Within California’s naturally-productive foodshed, a locally-sourced taco could be available in San Francisco year-round, according to Fletcher.

But the class’s presentation challenged the philosophy that local is always better.

In considering ecology and the realities of a global economy, the class expanded the calculation of each ingredient’s carbon footprint to encompass not only the number of miles traveled to reach the consumer but also the energy used in the growing, harvesting, manufacturing and distribution processes.

A recent study by engineers at Carnegie Mellon University showed that only 4% of all the greenhouse gases emitted by the food industry come from transporting food from producers to retailers.

To grow avocados local to New York City, for example, imagine the energy it would take to mimic the climate of Chile in the middle of winter, Yu and her classmate Annalise Aldrich pointed out.

“Sometimes it is more energy efficient to get a tomato from Central America than from a greenhouse in your own backyard,” said Yu.

With large-scale production and specialization, a region can take advantage of economies of scale and build support networks for manufacturing and distribution that reduce energy use.

A 2008 study by George Mason University found that due to the efficient means of transport involved in high-volume shipment and trucking, it is possible that the least efficient portion of the ingredient’s journey is each individual shopper’s trip from the grocery store to home.

Food that is mass-produced does not necessarily have the carbon footprint we may assume, even taking into account transportation. But labor practices and benefits to the regional economy may persuade some to continue their pursuit of locally grown food.

Fletcher admits the research is far from complete and would like to teach a follow-up class to continue the tacoshed project, focusing more specifically on labor practices and energy use.

“Our intention is to trace this back to the hands and faces behind these products. Future research would look into that,” said Fletcher, floating the idea of eventually publishing a book to present the class’s findings.

You can follow the conversation and future developments of the research at

Maps and graphics created by Rachael Yu, Annalise Aldrich, Teresa Aguilera (Rebar), and Fletcher Studio.

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Born in the central valley of Massachusetts and raised in Tidewater Virginia, Garrett attended public schools before graduating from the University of Virginia. Wandering and working in various national parks, tutoring kids on the playgrounds of Dublin, and teaching English to 3rd graders in China eventually led to some temporary confusion, and a re-settling as a community journalist.

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  1. Very nice informational piece. To all of our high school Spanish students, support your local taco trucks. If you are not fluent, place your order en espanol. You will be much appreciated.

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  2. Chris: Agreed. I was intrigued by the teaser about how local isn’t always the most ecologically correct, but if you stick with seasonal, it seems to me that local is still the best way to go. Now if I only had the time and discipline to do it. . .

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  3. Zig. You sound like an #$$. Why do brown or black people do what they do? Is it because of the color of their skin? I know plenty of white people who don’t have an intellectual bone in their bodies. Chris makes the point that these students somehow missed. You eat what is in season in your local area and the carbon footprint gets smaller. We, as human animals, evolved with this type of diet well before mass production and transportation. No matter what color your skin, healthy is healthy.

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  4. It’s important for people to know where their food comes from and what they put in their bodies so it’s I’m glad to see people looking into something as simple as a street taco. If we are going to fight health problems such as obesity and diabetes in poor neighborhoods, then we have to get away from the attitude that intellectualizing this kind everyday thing is somehow “white”.
    I’m still not sure what to think about the results, especially when they suggest that some foods may be more sustainable simply due to the energy that is used to grow and deliver them, but I will certainly share this with others. Interesting stuff.

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  5. This is very interesting. I believe this study is overlooking one thing though: the most energy-efficient approach to food is to eat local foods – *when they’re in season*. It may indeed be more efficient to get an avocado from Chile in the middle of winter, but it would be more efficient still to not eat avocados until they are in season where you live.

    Most Americans have grown detached from the idea of seasonality, but it is a crucial component when looking at food from a holistic, environmetally-minded approach.

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