Last week, Kitchen Table Talks gathered in San Francisco to discuss “The Meat of the Matter”: How our food system is structured to support industrial animal production and what alternative solutions exist, including reducing our meat consumption and supporting sustainable ranchers. We also heard new data underscoring meat’s deleterious environmental effects.

Leading us in conversation was Kari Hamerschlag, a Senior Agriculture Analyst working in the Environmental Working Group’s California office, who explained how she came to work on this subject 25 years ago after reading Francis Moore Lappé’s Diet for a Small Planet: “I was struck by the information in the book about the massive resources—water, fertilizer and pesticides, and fuel that goes into growing the feed that goes into producing a pound of beef and how highly inefficient and environmentally harmful the process is to get the protein we need,” Hamerschlag said. “Lappé argued convincingly to me that it would be much better to use at least some of those resources to grow food for hungry people rather than for animals.” She was so inspired that when she graduated from college, she drove cross-country and went to work for Lappé’s institute—Food First.

In Hamerschlag’s view, Lappé’s arguments are now more relevant than ever as meat production is central to a growing global water, energy, climate change—and food crisis. Next year, EWG will publish a “Meateaters’ Guide to Climate Change and Health,” which will quantify the amount of greenhouse gases (GHGs) associated with a typical serving of beef or pork or chicken—from the production of the fertilizer to the processing, transport and cooking, and waste of that product—so that the public can understand with greater certainty how changes in our individual diets affect the planet.

Bottom line: Eat lower on the food chain. Factory farmed lamb and beef, have the highest GHG impact—more than twice that of pork and chicken and more than five times that of veggie proteins—like beans, lentils and tofu, which have very low emissions. Cheese consumption has the third largest impact, when compared by weight. Waste accounts for about one-third of overall emissions associated with a pound of beef or chicken. “This is because a tremendous amount of resources go into producing wasted food which then ends up in the landfill generating additional methane,” Hamerschlag said. “Besides reducing our demand, reducing waste would be the other critical thing we need to do as a society to combat climate change and reduce the negative impact of agriculture.”

Hamerschlag explained the myriad problems with industrial animal agriculture: Nearly 149 million acres (or half of all crop land) is used for growing animal feed for U.S. livestock. Roughly 17 billion pounds of nitrogen fertilizer is needed to grow the feed—which generates nitrous oxide, a GHG 300 times as potent as carbon dioxide. “The pesticides and fertilizers often end up as runoff which pollutes our groundwater and waterways,” she said. “We now have a ‘dead zone’ in the Gulf of Mexico the size of New Jersey—where no marine life can live due to the lack of oxygen, largely a result of the phosphorous and nitrogen fertilizer used for grain production. And all of this grain is subsidized with our tax dollars—$45 billion worth over the past 10 years.”

Animals also generate huge amounts of manure, which creates nitrous oxide and methane, a GHG gas 25 times as potent as carbon dioxide. “Iowa’s 5,000 confined hog facilities generate over 50 million tons of raw waste or 16.7 tons of animal manure for every resident,” she said. “But unlike human waste, waste from animals is not generally regulated and the manure, which is either stored or spread on the fields, can leach all kinds of pollutants—such as antibiotics, metals like arsenic and selenium, and especially nitrogen and phosphorous directly into groundwater that affects drinking water.”

Hamerschlag noted that the meats that are most energy intensive are also worse for our health and may be contributing to the increased burden of chronic and acute disease in the U.S. Between 1950 and 2007, per capita meat consumption in the U.S. increased an astounding 78 pounds per person per year and world meat consumption is expected to double by 2050. The health consequences from the overconsumption of meat—obesity, coronary heart disease, and cancer—are now well documented. In addition, the non-therapeutic use of antibiotics in animals (70 percent of all antibiotics used in America are used in meat production) is also posing a serious threat to human health.

Kim O’Donnel, a trained chef, longtime journalist, and the author of the new book, The Meat Lover’s Meatless Cookbook, took the conversation from the theoretical to the personal: She grew up eating meat at every meal (her mother gave her T-bone steaks to gnaw on when she was teething as a baby), battled high cholesterol, and lost her father to a heart attack when he was 37. Her mother is now with a partner who loves meat and who has had several heart attacks.

O’Donnel explained the importance of reducing meat consumption for health, personal, and environmental reasons and said she wrote the book for her mother’s partner and for others, the hypothetical “Mr. Sausage”—the person who can’t imagine not eating meat every day, several times a day. “The idea is that you can still have your meat—still have your T-bone if you want it,” she said. “But I wanted to give creative, delicious ways for meat eaters, like myself, to take at least one day off a week from eating meat. And once you start, you feel better and your body will thank you.” She noted that reducing meat consumption by just 15 percent is good for your health and the planet.