Switching to compact fluorescent bulbs. Biking to work. These are basic tactics in the battle against global warming. But what about dinner? Food is often overlooked in the race to cut energy consumption and greenhouse-gas emissions. And yet, switching from a diet high in animal products — particularly beef — to a diet of mostly vegetables, grain, and poultry is tantamount to trading in a gas-guzzling Yukon XL for a hybrid Prius.

A meal's carbon footprint all starts with how its ingredients are produced. Before it even hits the road, the food you consume requires vast amounts of fossil fuel to grow and process: Fertilizers, pesticides, farm machinery, processing, and packaging all eat up their share. In fact, transportation accounts for only 11 percent of foods' carbon footprint, while the production phase makes up 83 percent. And although all foods require energy to be produced, some require much more than others: Producing a single cheeseburger sends a hefty 10.7 pounds of carbon dioxide (CO2) into the atmosphere. A family of four that cuts out burgers once a week saves the planet 2,225 pounds of carbon emissions a year — the equivalent of unplugging your fridge for 365 days. Unrefined plant-based foods, on the other hand, require much less energy. A veggie stir-fry of carrots, broccoli, and peppers causes only 1.5 pounds of CO2 emissions.

Did you know?

  • In our current system, food travels an average 1,500 miles from field to fork.
  • U.S. agriculture currently emits about 925 billion pounds of carbon dioxide each year from crop and livestock production.
  • Packaging is responsible for emitting 24,200 tons of greenhouse gases every year.
  • In 2000, the global food system produced 3,800 calories per U.S. citizen per day, up 800 calories since 1957.
  • Sources: Cool Foods Campaign; USDA Agriculture Fact Book.

“Our industrial food system has a very large ecological footprint. We need to fundamentally change the paradigm,” says Frederick Kirschenmann, a distinguished fellow at the Leopold Center for Sustainable Agriculture at Iowa State University and president of the Stone Barns Center for Food and Agriculture in Pocantico Hills, New York. That change starts at home by making meal choices with “low carbon,” rather than “low carb,” in mind.

The happy news is that a low-carbon diet is a win-win: It's good for Mother Nature, and it's good for you, too. “Personal health and planetary health are deeply connected,” says Kate Geagan, MS, RD, coauthor of Go Green, Get Lean: Trim Your Waistline with the Ultimate Low-Carbon Footprint Diet (Rodale, 2009). And you don't need to bake vegan casseroles in a solar-powered oven to make a difference.

Next: Eat less beef, more plant-based foods

Eat less beef, more plant-based foods. Americans, on average, eat more than 200 pounds of meat per person each year — 66 pounds of it beef. By some estimates, we eat an average of two ¼-pound burgers a week. Behind every T-bone, there's a burning trail of fossil fuel. To start, growing the copious amounts of corn needed to feed cattle requires synthetic fertilizers and pesticides made from fossil fuels. It takes 32 pounds of feed to produce 4 pounds of beef. Then there's the matter of planting, harvesting, processing, packaging, and transporting all that feed. Ultimately, it takes ten times the amount of fossil fuels to produce 1 calorie of beef than it takes to produce 1 calorie of grain.

What's more, through their natural digestive process, cows belch huge amounts of methane, an even more potent heat-trapping gas than CO2. Livestock contribute 18 percent of the planet's total greenhouse-gas emissions (GHG) — more than all the planes, trains, and automobiles combined.

Make a balanced choice: Dine on red meat sparingly, says Geagan. The health benefits — including preventing heart disease, diabetes, and certain cancers — of eating less red meat and more fruits and vegetables are well documented. For starters, try cutting out one or two red meat-based meals per week. Geagan suggests substituting grilled portobello mushrooms for meaty burgers or simmering beans and veggies together to create a hearty chili. (For additional ideas, check out Delicious Living's vegetarian recipe archive.)

Eat whole foods; limit processed products. Energy-intensive processed foods, clustered in the center of the grocery store, are high in calories and low in nutritional benefit, says Anna Lappé, author of Grub: Ideas for an Urban Organic Kitchen (Tarcher/Penguin, 2006). “To take an apple and turn it into a frozen apple turnover requires a tremendous amount of energy,” adds Geagan. Freezing, drying, canning, and refining — as well as shrink-wrapping and boxing — take energy.

Lappé also points to the thorny issue of palm oil, an ingredient used in place of unhealthful trans fats in some “healthy” processed foods. In Malaysia and Indonesia, where nearly 90 percent of the world's palm oil is produced, carbon-sequestering rainforest and peat bogs are being destroyed to make way for palm-oil plantations.

Make a balanced choice: Michael Pollan, author of In Defense of Food (Penguin, 2008), recommends shopping the periphery of the supermarket, where you find energy-efficient whole foods — fruits, vegetables, and fish. If you must buy processed products, Lappé suggests her “rule of thumb”: Avoid those with ingredient lists longer than the width of your thumb, particularly ones filled with unpronounceable ingredients.

Eat locally and seasonally; avoid air-freighted food. The fossil fuels burned to ship your lobster from Maine or your cherries from South America exact a heavy price on the environment. Flying food 5,000 miles releases more than 16 pounds of CO2, while food that is transported less than 150 miles by truck produces less than a pound of CO2 emissions. The issue of food miles can be complicated, however: In one study, tomatoes shipped from Spain to the U.K. had a lower carbon footprint than local hothouse tomatoes. Yet when you buy local, you're supporting nearby small-scale sustainable farmers.

The enthusiasm of the “locavore” movement is commendable, but going local won't solve it all. The types of foods you choose still make a tremendous impact. A 2008 study in the journal Environmental Science and Technology found that “shifting less than one day per week's worth of calories from red meat and dairy products to chicken, fish, eggs, or a vegetable-based diet achieves more GHG reduction than buying all locally sourced food.”

Make a balanced choice: Eat produce in season, when it is less likely to have been shipped long distances. Whenever possible, favor local produce at the store.

For fish, go lower on the food chain. While it's certainly important to go local and seasonal with seafood choices, doing so can be tricky — especially if you live in a landlocked state. Wherever you live, the best solution is to eat lower on the food chain, says Helene York, foundation director for the Bon Appétit Management Company, a food service group that serves some 80 million meals a year based on a low-carbon diet. “The energy required to fish high trophic-level species like tuna and deep-sea fish like Chilean sea bass is enormous,” says York.

Make a balanced choice: York recommends clams, mussels, and oysters, which require “practically zero” energy to farm. Other good choices are herbivorous fish, like tilapia and catfish; and species low on the food chain, such as mackerel, herring, and sardines. If you must have your pan-seared salmon, ideally it has been flash frozen at sea and transported in a container ship instead of a jumbo jet, says York. And skip the shrimp cocktail, she says. Imported shrimp can have an even higher carbon footprint than beef.

Eat small-scale local organic. Organic farming has the potential to use one-third fewer fossil fuels than conventional farming. Organic practices create healthy soil that sequesters carbon while eliminating energy-intensive synthetic fertilizers and pesticides. In a 28-year field study conducted by the Rodale Institute that compared side-by-side conventional and organic plots, the organic systems showed an increase in soil carbon of 15 percent to 28 percent, while the conventional system showed virtually no increase at all. The Rodale Institute estimates that converting just 2 acres of cropland to organic production is equivalent to taking one car off the road.

But you can't rely on the USDA Organic label alone to assure a food's low carbon imprint, because the industrialization of organic farming has changed the energy algorithm. Small-scale sustainable farms that use on-site compost can mitigate GHG emissions better than large-scale operations that need to truck in compost and use big machinery to weed fields and harvest crops. “There's a very compelling reason to go organic. Overall it's better for the planet,” says Eugene Cordero, PhD, coauthor of Cool Cuisine: Taking the Bite out of Global Warming (Gibbs Smith, 2008). “But if you're talking strictly from a carbon dioxide-emissions standpoint, it's a little unclear.”

Make a balanced choice: Health- and planet-wise, organic is still the best choice. Whenever possible, buy seasonal organic produce grown locally on small-scale farms. Look for “local” on produce displays or ask your retailer for a rundown of fresh, organic items sourced locally.

Reduce waste. The USDA's Economic Research Service estimates that our current food system produces approximately 3,800 calories per person per day and that roughly 1,100 of those calories are lost due to spoilage, plate waste, cooking, and other losses. What's more, organic matter emits methane when heaped in a landfill. In fact, landfills are second only to cattle in producing methane. In your garden, organic food matter can be composted into nitrogen-rich fertilizer, a process that doesn't create emissions. (For tips on how to start composting at home, turn to “Why Compost?” on page 50.)

Make a balanced choice: “Take a bit less,” says Geagan. At the grocery store, buy only what you need. Avoid the temptation of buy-one-get-one-free offers. At home, dole out smaller portions, eat leftovers, and compost food waste.

For more tips and recipes for lowering your food footprint, visit our Green Living archive.

Helen Olsson is a freelance writer based in Boulder, Colorado.