Not every student in line at the University of Redlands cafeteria was ready for self-sacrifice to save the planet.
"No hamburger patties?" asked an incredulous football player, repeating the words of the grill cook. He glowered at the posted sign: "Cows or cars? Worldwide, livestock emits 18% of greenhouse gases, more than the transportation sector! Today we're offering great-tasting vegetarian choices."
The portabello burger didn't beckon him. Nor the black-bean burger.
"Just give me three chicken breasts, please," he said -- and with that, swaggered off to pile potato wedges onto his heaping plate.
Although this perhaps wasn't the most accepting reaction, it resulted in the desired dietary shift as Bon Appétit Management Co. rolls out its new Low Carbon Diet in 400 cafes it runs at university and corporate campuses around the country. Chicken, it turns out, has a lower carbon footprint than beef.
Conscientious consumers who want to tread lightly are increasingly concerned about their own carbon footprints. They've changed lightbulbs. They covet a Prius more than a Porsche. Now their anxiety over global warming has shifted to the supermarket and dinner table.
The global food and agriculture system produces about one-third of humanity's contribution to greenhouse gases. So questions about food are shifting from the familiar "Is this good for me?" or "Will it make me fat?" to "Is it good for the planet?"
But what's the right thing to do? It's not just paper versus plastic anymore. Is throwing out leftovers better than taking them home in a plastic container? Is refrigerated better than frozen? A French brie sandwich or chicken salad?
Sensing this, the country's major food service companies are talking about energy efficiency, waste reduction and, now, how to reduce carbon emissions associated with the food they serve.
Changing the meaning of "carb" in "low-carb" has been kicking around for years. Those who preach eating local, such as the locavores, have hogged much of the attention with a focus on "food miles," the distance that food travels from farm to fork.
Food science has begun to look beyond transportation, to the smorgasbord of contributors to carbon dioxide and other gases with even greater atmospheric warming potential, such as methane.
Researchers tally emissions related to each of hundreds of steps in the life cycle of various foods, from the energy-intensive process of manufacturing fertilizer for crops to the leftovers scraped from plates that end up rotting in a landfill, burping methane.
As they perfect these life-cycle assessments, scientists are ready to answer the question raised by a cartoon-book character in a Roy Lichtenstein-inspired poster outside the university cafe: "Is my cheeseburger causing global warming?"
It was a sparkling spring day at the Getty Center in the Brentwood hills. Instead of heading into the sunshine for their lunch break, museum staffers filed into a darkened auditorium to hear a lecture: "Play With Your Food."
The crowd appeared to be a thoughtful bunch, many of them foodies, and more receptive than a famished football player to weighing the environmental and social consequences of their food choices.
Helene York took the stage with her PowerPoint slides, fulfilling the directive of Fedele Bauccio, Bon Appétit's blunt-talking chief executive: "Customers make choices for us. We need to educate them."
York, who directs the Low Carbon Diet initiative, explains that the diet is to slim down the company's greenhouse gas emissions by 25%, beginning by changing the 80 million meals it serves a year.
"That sounds like a lot," she said. Yet it's nothing compared with what can happen if Bon Appétit persuades its parent company, Compass Group, to follow suit, as it did with the switch to sustainably caught seafood. Compass Group is the largest food-service company in North America, with 8,000 accounts including sports arenas, hospitals and Chicago's public schools. Other food service companies, such as Sodexo (Marriott), are also considering menu changes.
To start, Bon Appétit has targeted those items with the biggest impact. That means reducing the amount of beef and cheese.
"Inherently, beef and lamb are worse than every other form of animal protein," York said. The reason? These ruminants incessantly belch methane gas. She points out that methane has 23 times the global warming potential of carbon dioxide.
Vegetarians think they get a free ride, she said. Yet if they nibble on a grilled cheese sandwich, they buy into the same industrialized system, which is fertilizer-intensive. Overuse of fertilizer releases nitrous oxide into the atmosphere, a gas that has 296 times the warming potential of carbon dioxide.
"Does your sushi get more frequent-flier miles than you do?" another poster flashes on the screen. It draws a laugh from the audience -- until York explains that Bon Appétit is phasing out fresh seafood brought in by air freight.
About 80% of the seafood consumed in the U.S. is imported, and nearly all of it takes to the skies. That means delicate slabs of fresh halibut and salmon carry a long contrail of aircraft exhaust to the table. Bon Appétit is setting up supply lines to buy Alaskan salmon fillets and other fish frozen at sea. York said top chefs swear that diners cannot tell the difference if fish is properly prepared.
Bon Appétit, which long ago joined the buy-local movement, is slowly eliminating out-of-season produce flown from Chile and other Latin American countries and cutting by half its imported tropical fruit, such as bananas, pineapples and papayas.
It has also phased out imported bottled water, she said. No more San Pellegrino. No more Perrier.
"Voss water, what's that? It's water that comes in a fancy glass bottle from Norway, of all places," York said, revealing her Brooklyn accent. "Don't we have enough water here?"
York told the group that plastic packaging, despite its bad reputation, is only a minuscule part of the carbon footprint. So if it's a question of taking leftovers home in plastic containers or leaving the food to be thrown away, she said, take it home.
"The food with the highest carbon footprint is the food we don't eat," she said, explaining that 3% of America's energy use is tied up in food trucked to the dump.
Although Americans are piling more food onto their plate than ever, studies show that not all of these extra calories are expanding waistlines. As much as 25% of those leftover peas and carrots and gristle ends up buried in the landfill. Deprived of oxygen, the mash of rotting food produces methane gas.
Bon Appétit has begun to reverse the trend of super-sized meals. Burgers on many college campuses, for instance, have been downsized from one-third to quarter-pounders, with prices adjusted accordingly.
York, a Harvard- and Yale-educated MBA, is part carbon cop -- "I spent a lot of time beating up our suppliers" -- and part mom, reminding customers that their mother was right: You should eat more vegetables. You shouldn't waste food.
She's also a food detective. She leads the company's effort to track the origins of Bon Appétit's food purchases to assess carbon emissions.
That's not always easy. She has found confounding things, such as San Joaquin Valley-grown tomatoes that get shipped to Massachusetts and back because of the peculiarities of the nation's food distribution system.
She isn't the only one who's frustrated. The Tesco supermarket chain in England wants to affix a carbon score to each item on its shelves but has been bogged down in the complexity of the task.
The U.S. Congress in 2002 took a step toward unmasking food supply lines by passing a law requiring meat and produce to carry a label revealing the country of origin. But under pressure from food suppliers and grocery chains, legislators have repeatedly postponed the law's implementation for all but seafood.
That leaves supermarket shoppers staring at well-stocked shelves from around the globe without any sure way to tell where the food is from.
Bon Appétit has brought together a group of scientists to help consumers sort through the thicket with an online carbon calculator at www.EatLowCarbon.org.
Later in the week, York is off to Redlands to train the Bon Appétit managers from various university campuses about today's national rollout of Low Carbon Diet day. The University of Redlands cafe is the test case. A poster invites students: "You've changed your light bulbs, now change your lunch. Find out how food choices affect climate change."
On this day, bananas have been replaced by local strawberries. Next to slices of cheese and pepperoni pizza were "cheese-less" options, a slice of double tomato, another with pesto and chicken. And then there was the grill station, missing its most popular item: all-beef burgers.
"The kids, they love their burgers," said Luis Delgado, a gregarious and popular grill cook who spent much of lunchtime dishing out disappointment. "I tell them they'll get them tonight."
Kaethe Selkirk, a freshman studying art history, and her boyfriend, Billy Kingsborough, settled for turkey burgers. But neither seemed willing to cut out their regular off-campus trips to munch on Double-Doubles at In-N-Out Burger.
"No one is going to admit that they don't care," she said. "It's not socially acceptable to not be for saving the planet."
How about reducing waste?
Rachel Rocklin, a petite senior with silver toenail polish, plopped down her tray on a conveyor belt, leaving a half-eaten turkey burger and half a bowl of broccoli soup.
She walked past the sign that explained that the university's food program produces 15 tons of waste each week. "The natural tendency is to fill up your tray. However, is that the right amount of food for you or the planet?"
She stopped, took it in and nodded.
"I would rather see it go down the conveyor belt than make me fat," Rocklin said. "I guess next time I could ask for a half a burger."