Peter Singer, the groundbreaking ethicist whom The New Yorker calls the most influential philosopher alive teams up again with Jim Mason, his coauthor on the acclaimed Animal Factories, to set their critical sights on the food we buy and eat: where it comes from, how it is produced, and whether it was raised humanely. The Ethics of What We Eat explores the impact our food choices have on humans, animals, and the environment. Recognizing that not all of us will become vegetarians, Singer and Mason offer ways to make healthful, humane food choices. As they point out: You can be ethical without being fanatical. “An absolutely indispensable book for anyone who thinks about what they eat ... I cannot recommend it highly enough.” — Jeffrey Moussaieff Masson, author of When Elephants Weep and Raising the Peaceable Kingdom “. . . vital, urgent, and disturbing.” — Dorothy Kalins, New York Times “. . . clear and persuasive.” — Susan Salter Reynolds, Los Angeles Times “A no-holds-barred treatise on ethical consumption.” — Publishers Weekly PETER SINGER, is author of  Animal Liberation  and coauthor of  Animal Factories,  is one of the highest-profile writers on ethics today, regularly drawing fire for his views on such hot-button issues as abortion, euthanasia, war, and animal rights. Born in Australia, he has taught at Princeton University since 1999 and lives in New York. JIM MASON is the author of  An Unnatural Order  and the coauthor of  Animal Factories.  He is also an attorney and the fifth generation of a Missouri farming family. He lives on Virginia's Eastern Shore. PART I EATING THE STANDARD AMERICAN DIET 1 JAKE AND LEE There is no downtown, no bustling public square, no quaint historic district in Mabelvale, Arkansas. The "main drag" is Baseline Road--four lanes of traffic running through a corridor of gas stations, convenience stores, and strip malls in the urban sprawl southwest of Little Rock, to which it was annexed in 1980. Sixty percent of Mabelvale's 5,000 inhabitants are white, 25 percent are African-American, and 10 percent are Latino; they live in homes worth around $75,000 and earn about $30,000 annually. Among the residents of Mabelvale is the family of Jake Hillard, 36, and Lee Nierstheimer, 26. We chose them for their basic meat-and-potatoes diet-- sometimes called the Standard American Diet, or SAD. Though the term lacks a precise definition, it is the most widely eaten diet in America. The Standard American Diet is high in meat, eggs, and dairy products. Carbohydrates such as bread, sugar, and rice are usually eaten in refined form, which, combined with a low intake of fruit and vegetables, means that the diet is low in fiber. Frequent consumption of fried foods contributes to a high intake of fat, with as much as 35 percent of calories coming from fat, most of it saturated and much of it animal fat. A burger on a bun with a serving of french fries, followed by an ice-cream sundae and washed down with a can of cola, fits squarely in this American tradition. It's a quick and easy way of putting enough food in your stomach to feel satisfied. With America's low prices for meat, eggs and dairy products, it's not expensive either. We met Lee Nierstheimer at his place of work, a local firm that makes custom-made handling systems and conveyors for major manufacturers. A man of medium height and build, he has a boyish face and a full head of straight brown hair. He tells us that had we come a few months earlier, he would have been at work in the machine shop, welding and bending metal into the sizes and shapes called for in customers' specifications. But he has recently been promoted and is now an engineer, designing and drawing plans for the equipment manufactured by his company. It's the end of the working day and he takes us back to his home, where he lives with his wife, Jake, and their two children, Katie, 2, and Max, 6 months. They are at the end of a dead-end street in a neighborhood of modest homes that date from the 1950s and 1960s. On the corner is a little old house renewed by white vinyl siding, next to a tattered blue mobile home, then a neat, small, brick house, then a couple more clad in vinyl, and so on. At their gate we're greeted by a couple of very friendly dogs: one looks like a mid-sized St. Bernard--large, fluffy, brown-and-white. "That's Baggie," Lee says. The other one, Annie, a Border collie with maybe a bit of Australian shepherd mixed in, is the current neighborhood hero--she roused several people in time to catch a burglar in the act of breaking and entering a house up the street. The yard, walkway, and stoop are cluttered with bright, primary-colored plastic tricycles, wagons, miniature chairs, balls, and toys. Inside, there's more of the same, with Jake--snugly curled up in an overstuffed chair--breast-feeding baby Max. At her feet, Katie is engrossed in watching Finding Nemo on the VCR. A black-and-white cat dozes among the toys on the sofa. Lee immediat