Eating green: the case for a plant-based diet.
Most people know that beef increases the risk of heart disease. And some people know that much of the livestock industry mistreats animals.
But few realize that raising animals for food also takes a heavy toll on the environment. It consumes enormous quantities of fuel, fertilizers, pesticides, water, and land. If the entire world's population were to eat as much meat as Westerners, we'd quickly run out of land and irrigation water.
Here's why cutting back on beef--and, to a lesser extent, poultry, fish, dairy foods, and eggs--is good for you, for animals, and for the Earth.
Six Arguments for a Greener Diet, CSPI's latest book, explains why eating fewer animal--and more plant--foods protects our health, our planet, and the welfare of the animals we raise for food. In this interview, author Michael Jacobson, Executive Director of the Center for Science in the Public Interest (the nonprofit publisher of Nutrition Action Healthletter), lays out some of the book's key points.
Q: Which food harms the environment the most?
A: Grain-fed beef. It's an environmental debacle for two principal reasons: what goes in and what comes out.
Cattle spend three-quarters of their lives on the range, eating grass, just as they always have. But they spend their final months in a feedlot that gradually replaces up to 90 percent of the grasses they've been eating with corn, soybean meal, and a dollop of drugs.
Growing that grain requires vast amounts of land, irrigation water, pesticides, and fertilizer. Some of those pesticides and fertilizers--plus manure, antibiotics, hormones, and eroded soil--end up polluting our water or air.
Q: Does it take a lot of grain to produce a steak?
A: It takes about 7 pounds of grain to put a pound of weight on cattle in feedlots. But because much of the weight gain goes into bone, organs, and other inedible tissues, it takes even more feed to produce a pound of beef.
Globally, most grains are eaten directly by people. Outside the United States, livestock consume only 21 percent of total grain production. In the United States, about 66 percent of grains and hay grown on our nation's farms ends up being fed to animals.
Q: And growing grain takes a lot of land?
A: Lots. Most of the Midwest's grasslands and forests have been replaced by grain farms. The 100 million acres of feed crops that we grow for livestock rob topsoil of nutrients and cause erosion.
To compensate for the soil's lost productivity, farmers apply fertilizer--and lots of it--in the form of chemicals, manure, and treated sewage sludge. About half of all fertilizer applied in the United States is used to grow the grain--mostly corn-that's fed to livestock. It takes one-third of a pound of fertilizer to produce a pound of cooked beef.
Q: How does fertilizer harm the environment?
A: Fertilizers take a great deal of energy to produce. The energy needed to manufacture the fertilizer that's used to grow feed grains for animals in the United States could provide a year's worth of power for about one million Americans.
And when fertilizers are used on farms, they pollute the air and they suffocate water life.
A: The nutrients in fertilizer feed the growth of algae, which then die off. When the algae decompose, oxygen levels in the water decline. So much fertilizer from Midwestern corn farms washes down the Mississippi River that the Gulf of Mexico now has a poorly oxygenated "dead zone" the size of New Jersey. Bottom-dwelling sea life cannot survive there.
Q: How do teed grains affect our water supply?
A: In the arid West and Great Plains, farmers use large amounts of irrigation water to grow feed grains. That depletes underground aquifers. That water could be put to better use in cities or for industry.
It takes about 18,000 gallons of rain and irrigation water to produce a pound of beef. Together, raising livestock and irrigating the crops they eat consume over half of all freshwater used in the United States.
Q: How do pesticides harm the environment?
A: They disrupt ecosystems and harm wildlife. For example, atrazine is one of the most widely used herbicides. Tyrone Hayes and his colleagues at the University of California at Berkeley found that low levels of atrazine cause gonadal and limb abnormalities and hermaphroditism in frogs. He calls it "chemical castration" and says that it may just be a matter of time before we find that atrazine harms humans.
Q: How does "what comes out" of livestock cause problems?
A: The 50,000 cattle that reside in a large feedlot produce as much manure as a city of several million people. Not surprisingly, that creates a stench that undermines the quality of life for everyone who lives or works nearby.
Q: Would raising cattle on pasture rather than in feedlots lessen the ecological damage?
A: Yes, to a great extent. The manure would be spread out on the fields, where it would fertilize grasses. But even then, during the coldest months cattle would probably have to be fed hay, which is grown with fertilizer, pesticides, and irrigation water.
And the cattle would still emit methane, a potent greenhouse gas. In fact, cattle that eat grass and roughage release more methane than cattle on a high-energy feedlot diet, because grass-fed cattle take about 10 to 20 percent longer to reach market weight.
Those longer lives also mean more manure--about 60 pounds per day or 4,000 more pounds per animal. But at least that manure is dispersed widely on pastureland.
Q: How does beef contribute to global warming?
A: Carbon dioxide and other gases trap heat in the atmosphere--a process that is slowly raising the Earth's temperature and causing profound changes in our climate and environment. While automobiles and coal-fired power plants are the worst culprits, agriculture also contributes.
When it comes to global warming, methane is 23 times as potent as an equal amount of carbon dioxide. And farm animals--mostly cattle--account for 19 percent of all methane released in the United States. In 2000, the methane released from livestock and manure lagoons caused as much environmental damage as the carbon dioxide from about 33 million automobiles.
Nitrous oxide--from decomposing manure and from the fertilizer that is applied to cropland--has an impact on global warming that is 300 times as powerful as an equal amount of carbon dioxide. Nitrous oxide--largely from cattle--accounts for 6 percent of the greenhouse effect in the lower atmosphere.
Q: Has anyone estimated beef's impact on greenhouse gases?
A: According to University of Chicago geophysicists Gidon Eshel and Pamela Martin, every person who eats a typical American diet instead of an all-plant diet adds as much greenhouse gases as if he or she were driving an SUV instead of a less-polluting Toyota Camry.
If every American switched to an all-plant diet, we'd produce 430 million fewer tons of carbon dioxide per year. That's 6 percent of the nation's total emissions of greenhouse gases. It's not a huge share, but every reduction helps protect our planet.
Q: What if people just cut back on meat?
A: That would help. Compared to a typical diet, a low-meat diet uses 41 percent less energy and generates 37 percent less greenhouse gases and 50 percent less sulfur dioxide equivalents. Sulfur dioxide causes respiratory problems and acid rain.
Q: How much more energy does a meat-laden diet use?
A: Eshel and Martin calculate that it takes 1,600 calories from oil, gas, and other fossil fuels to produce 100 calories' worth of grain-fed beef. It takes about 500 calories from fossil fuel to produce 100 calories' worth of chicken or milk. But it takes only 50 calories to produce 100 calories' worth of plant foods.
Q: Does the way we raise pigs and chickens also harm the environment?
A: Yes, but less so than cattle. While pigs and chickens eat grain for most of their lives, at least they convert it to muscle more efficiently than cattle, which reduces the amount of grains needed. Still, their manure overloads the environment.
The liquid waste from factory-type pig farms is stored in what are euphemistically called lagoons. Foul odor aside, the lagoons emit ammonia, which reacts with sulfur and nitrogen to form gases that irritate our mucous membranes and contribute to smog and acid rain. And the lagoons occasionally rupture, dumping large amounts of stinking, bacteria-infested waste onto the soil and into streams.
Q: Does chicken waste also destroy water life?
A: Yes. In the big chicken-raising areas of the country, an arc stretching from Arkansas through the Southeast and up to the Delmarva Peninsula, manure is a major water pollutant.
On the Delmarva Peninsula--which includes parts of Delaware, Maryland, and Virginia--the waste of 600 million chickens releases some 20,000 tons of ammonia each year. Experts call the ammonia a silent killer of the Chesapeake Bay.
Q: Do dairy farms pollute the environment?
A: Yes. Manure is a huge problem when too many dairy cows are raised in too small an area. California's San Joaquin Valley, home to one-fifth of America's dairy cows, now competes with Los Angeles and Houston for having the most polluted air in the United States.
Q: What are the environmental consequences of eating seafood?
A: Overfishing is endangering the survival of entire species of fish, and the problem will only increase as the world's population expands and more people want to eat more fish.
Fish farms may be part of the solution, but they're also part of the problem. It's cruel to crowd thousands of freshwater fish into ponds. Farmed salmon may escape from their ocean pens and breed with wild salmon, narrowing the gene pool and endangering the wild salmon's ability to withstand environmental challenges. And some fish are fed fishmeal, which reduces the food supply for wild ocean fish.
Q: Are vegetarians healthier than meat eaters?
A: Vegetarians tend to eat healthier diets and to suffer lower rates of key diseases, according to studies of Seventh-day Adventists in California and others. About half of all Seventh-day Adventists are vegetarians.
The vegetarian Seventh-day Adventists consume more fruits and vegetables, more fiber, and less saturated fat and cholesterol. They also tend to weigh an average of six pounds less and have lower blood pressure and lower levels of LDL cholesterol, which is the bad kind. So it's no surprise that they have lower rates of heart attacks and diabetes and live about three years longer than non-vegetarian Seventh-day Adventists.
Q: Could the vegetarians live longer because they do other things that protect their health?
A: Yes, it's possible that the vegetarians are healthier because they follow a healthier lifestyle than the non-vegetarians, even though researchers try to account for those differences. But there's overwhelming evidence that eating less red meat and more fruits and vegetables lowers the risk of disease.
Q: How much difference can diet make?
A: Red meat, dairy foods, and eggs are the biggest sources of saturated fat and cholesterol, which promote heart disease, the number-one killer in the United States. I estimate that eliminating saturated fat and cholesterol by not eating meat, dairy foods, poultry, and eggs would save about 65,000 lives per year.
What's more, replacing those animal foods with plant foods that are rich in vitamins, minerals, and fiber--which is absent from animal foods--would save thousands more lives every year.
Q: Are those nutrients in all plant foods?
A: No. I'm talking about fruits, vegetables, whole grains, nuts, and beans. We're consuming far fewer fruits and vegetables than we should be, and much of what we do consume is the least nutritious kind, foods like white--and often fried--potatoes and iceberg lettuce. While we eat enough, or more than enough, bread and other grains, 90 percent of them are made from refined, not whole-grain, flour.
Q: Are some vegetarian diets unhealthy?
A: Yes. Just think of those teenage vegetarians who live off foods like soda pop, white bread, sugary cereals, milk shakes, and french fries. But the average vegetarian eats a far healthier diet than the average omnivore.
Still, I'm not blaming animal foods for every ill. Reducing the high sodium content in foods, plant or animal, could prevent more than 100,000 deaths every year. And eliminating the trans fat that's found in partially hydrogenated oils could save another 25,000 to 50,000 lives.
Q: Is grass-fed beef healthier than grain-fed?
A: Yes. If you eat beef, make it grass-fed. It's typically much lower in saturated fat than choice or prime grade beef from feedlots. And marinating or moist cooking methods like braising help reduce any toughness. But beef of any kind appears to increase the risk of colon cancer, so don't think of grass-fed beef as a health food.
Q: Is meat a major cause of foodborne illness?
A: More than 1,000 Americans die each year from foodborne illnesses linked to meat, poultry, dairy foods, and eggs. It's easier for germs to spread now that huge meatpacking plants have taken over, because bits of hundreds of animals can end up in a single hamburger. And while fruits and vegetables are also a major cause of food poisoning, their germs often come from livestock manure.
We also have to worry that raising large numbers of poultry and pigs will increase the risk of deadly flu epidemics. The animals serve as reservoirs for germs, which can multiply and sometimes mutate and exchange genes in dangerous ways when livestock are crowded together.
Q: Is there anything wrong with skim milk?
A: Switching to skim milk is good for your health. However, from a public health point of view it's useless, because the milkfat that's removed isn't thrown away. It will turn up in that stick of butter or scoop of fatty ice cream. And if you don't consume those foods, someone else will.
Q: Isn't seafood healthy?
A: Yes, as long as it hasn't been fried in partially hydrogenated oil. Seafood is a good source of protein, it's low in saturated fat, and some species provide a bonus of omega-3 fats, which may lower the risk of heart disease. But tuna, swordfish, and some other species may be contaminated with enough mercury and other chemicals to harm fetuses and nursing infants.
Q: How about chicken?
A: It's fine, unless you get it from KFC, McDonald's, Burger King, or other restaurants that fry it in partially hydrogenated oil. Like seafood, chicken and turkey are good sources of protein and are usually lower in saturated fat than red meat. However, a large serving of chicken or turkey leaves too little room on your plate for vegetables.
Q: What harm do pesticides do?
A: Of the 511 million pounds of pesticides applied in 2001, roughly a third was used on the crops that feed livestock. Farmers have higher rates of lymphomas and prostate cancer.
The levels in food and water are minuscule, and their effects may be subtle and tough to identify. But those residues may increase consumers' risk of cancer, immune disorders, Parkinson's disease, and other health problems.
Q: Aren't pesticides more of a problem on fruits and vegetables?
A: No. Pesticides may be directly sprayed on produce, but fat-soluble pesticides in burgers, steaks, and milk actually pose the bigger risk. That's because pesticide residues accumulate in the fat of livestock that are fed pesticide-tainted feed grains.
Q: How do we treat livestock?
A: I think city dwellers would be shocked by the way most farm animals are treated. Once upon a time, cows, pigs, and chickens were raised in small numbers on small farms and were treated reasonably well.
Today, most animals spend their lives crammed together on factory farms.
Q: How are cattle treated?
A: Many cattle are castrated without painkillers. And many are branded, even though ear tags or retinal imaging is a better way to identify them. The animal is either pinned to the ground or constrained in a chute while the rancher impresses the brand into its hide using a blazing hot iron, which creates a third-degree burn.
And cattle spend their last few months on feedlots eating a high-grain diet that frequently causes stomach ulcers, liver abscesses, and hoof diseases.
Q: Do other animals have it worse?
A: Yes. At least beef cattle spend much of their lives in pasture. Almost all pigs are raised in small pens in huge sheds. They're constantly exposed to fumes from their manure and urine, which drop below the slatted floors. Their tails are often trimmed to prevent tail biting.
And pregnant and nursing pigs are housed in crates too small to even turn around in. Modern pigs never get a chance to walk around in the sun or rain or to root for food.
Q: What about chickens?
A: Broiler chickens are raised in huge sheds holding up to 50,000 birds. Growers don't change the floor covering in a broiler house during the course of a single flock's life--or even several flocks' lives. Feathers, feces, and feed all become mixed with sawdust. The high acidity of chicken dung that collects on floors can cause burns on the chickens' feet and legs. But those chickens can at least walk around.
Layer hens are usually crammed into little cages that hold about five hens, each with half a square foot of space, on average. They don't even have room to flap their wings. And wings sometimes break when they get caught in cage bars.
The farmers trim the birds' beaks to keep them from pecking other birds, even though debeaking causes acute pain that recurs when the bird eats.
Both broiler and layer chickens never get the chance to build nests, peck for bugs, or bask in the sun. And male chicks that hatch on egg-industry breeder farms go right into the disposal. The egg industry shreds millions of male chicks at birth every year.
Q: What about dairy cows?
A: Forget your childhood image of Bessie, the family dairy cow. Dairy farmers take calves from their mothers prematurely and cram them together in barns, rather than let them graze in pastures. The cows sometimes are injected with a growth hormone that increases rates of lameness and udder infections and reduces life spans.
To prevent crowded, stressed animals from injuring each other or their handlers, dairy cattle are dehorned, without painkillers or anesthetics. The nascent horn is gouged out, cut off, or burned off with either a hot iron or chemicals. Although many people think that horns are woody protuberances devoid of sensation, they are more similar to teeth. Their hard shell covers rich networks of blood vessels and nerves.
Cows' tails often become coated with dirt and excrement, so when they swish their tails to chase off flies, they fling the filth about, sometimes onto udders, which leads to an infection called mastitis. One common solution is to dock--or cut off--part of the tails.
Q: Is there a better way to raise cows?
A: Yes. Instead of docking tails, farmers could clean up dirty stalls. In Sweden, tail docking is forbidden, farmers must administer a local anesthetic or a sedative for dehorning, and cows must be kept on pasture for at least two to four months out of the year. Here, many dairy cows are kept indoors in a tiny space--less than a third of the footprint of the Mini Cooper, the tiniest car on U.S. roads.
Q: Do animals suffer at the slaughterhouse?
A: That's the final indignity. Near the end of their short and often miserable lives, livestock are crammed into crowded trucks lacking food and water. A small fraction of the animals are still conscious before they are killed, resulting in terrible pain. Those animals can also injure slaughterhouse workers.
Q: Aren't animals stunned before they're killed?
A: Yes, but the rate of killing in a typical modern slaughterhouse is breathtaking: 13,000 chickens per hour, 1,000 pigs per hour, 250 cattle per hour. At those speeds, it is likely impossible to ensure that every single animal is adequately stunned before it is killed. According to a report commissioned by the U.S. Department of Agriculture, in some plants as many as 8 percent of pigs, 20 percent of cattle, and 47 percent of sheep are not properly stunned.
Slaughterhouses stun broiler chickens by placing their heads in an electrified pool of water. After that, the chickens' necks are slit. Layer hens are not typically stunned, because their osteoporotic, unexercised bones may break when exposed to the electrical current. Instead, layers are conscious while their throats are slit.
Q: Don't those practices make meat and poultry cheaper?
A: The livestock industry is wickedly efficient, but at what price? Animals shouldn't have to suffer so that people can eat a little more cheaply.
Sweden, Denmark, and other European countries have adopted much more humane animal husbandry rules. In some countries, hens are not squeezed into tiny cages, pigs must be given straw for bedding, and cows get a sedative or local anesthetic before they are dehorned.
Eating fewer animal foods means that fewer animals will suffer. When we do eat animal foods, we should look for grass-fed beef, free-range pork and chicken, and cage-free eggs.
Q: What else could move Americans toward a greener diet?
A: The government could mount large-scale campaigns to encourage people to eat more plant foods. It could also offer economic incentives for farmers to shrink feedlots, lower the saturated fat in milk, and treat animals humanely (see p. 2).
Q: Do you recommend that everyone become a vegetarian?
A: Vegetarian diets, which include dairy foods and eggs, and vegan diets, which include no animal foods at all, offer major advantages. We should all move in that direction, but we don't have to become strict vegetarians.
From a health perspective, it isn't a problem to eat an occasional cheeseburger or hot dog, let alone a serving of grilled salmon or chicken. If you're going to remain an omnivore, at least look for lowfat versions of meat and dairy foods. And when you can, buy locally grown foods. If they're organically grown, it's better for the environment.
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|Title Annotation:||Six Arguments for a Greener Diet|
|Publication:||Nutrition Action Healthletter|
|Article Type:||Cover story|
|Date:||Sep 1, 2006|
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