The Environment

Land Utilization and Soil Erosion
One-half of the Earth's land mass is grazed by livestock.[1]
More than 60% of the world's rangelands were damaged by overgrazing during the past half century.[2]
Overgrazing is by far the most pervasive cause of desertification.[3]
35 pounds of topsoil are lost in the production of one pound of grain-fed beef.[4]
Pounds of edible product that can be produced on an acre of prime land: Apples 20,000; Carrots 30,000; Potatoes 40,000; Tomatoes 50,000;
Beef 250 [5]

Water Consumption
The number of gallons of water needed to produce one pound of edible product: Apples 49; Carrots 33; Potatoes 24; Tomatoes 23; Beef 2,500 [6,7]

Endangered Species
Between 19 and 22% of all threatened and endangered species are harmed by livestock grazing.[8]

Rainforest Destruction
5 million acres of rainforest are felled every year in South and Central America to create cattle pasture.[9]
Cattle ranching has destroyed more Central American rainforest than any other activity.[10]

Pollution
Manure produced by all farm animals in the US annually is roughly 10 times the waste produced by the human population.[11]

Resource Distribution
Resources used in the production of livestock:
33% of world's fish catch [15]
38% of the world's grain harvest [16]
Almost half of all energy expended in US agriculture [17]
12-16 pounds of grain and soy are needed to produce one pound of grain-fed beef.[18]
All 17 of the worlds major fishing areas have reached or exceeded their natural limits due to overfishing.[19]

   World Hunger

Approximately 40,000 people die each day worldwide due to hunger or hunger-related causes.[20]
10 billion people could be sustained from present croplands if all ate a vegetarian diet.[21]

   Health

Cholesterol
Amount of cholesterol in a 3 oz. serving of: T-bone steak 72 mg; Chicken 75 mg; Turkey 76 mg; Salmon 74 mg; Shrimp 166 mg All foods derived from plants (fruits, vegetables, grains, legumes, nuts, seeds) 0 mg [22]
Every time the blood cholesterol level rises one percent a corresponding risk of coronary heart disease rises two percent.[23]
A recent international conference of leading heart researchers concluded, "The optimal intake of cholesterol in the adult is probably zero." [24]

Protein Requirements
The most rapid human growth is during infancy. Nature's food for human infants is mother's breast milk which provides all the protein needed or 5% of the calories as protein.[25]
The World Health Organization of the United Nations recommends only 4.5% of daily calories be provided as protein. The National Research Council says 8-10%.[26]
Percentage of Calories as Protein: Tofu 43%, Kidney beans 26%, Chick peas 23%, Wheat 17%, Oatmeal 16%, Peanuts 18%, Oranges 8%,
Bananas 5%, Broccoli 47%, Mushrooms 38%, Green beans 26%, Tomatoes 18%, Potatoes 11% [27]
Frances Moore Lappe, who popularized the concept of combining proteins, provided updated research that protein combining is unnecessary in a healthy, varied vegetarian diet.[28]
Female meat-eaters at age 65 experience an average measurable bone loss of 35%.[29]
Female vegetarians at age 65 experience an average measurable bone loss of 18%.[30]

Pesticides & Food Contamination
Meat, poultry and dairy products contain the major source of pesticide residues in the western diet.[12]
Nearly half of all fish sampled by Consumers Union was contaminated with bacterial from human or animal feces.[13]
99% of US non-vegetarian mothers' milk has significant levels of DDT.
Only 8% of US vegetarian mothers' milk has significant levels of DDT.[14]

The Good News About Plant-Based Diets
A low-fat diet free of animal products can prevent, improve and/or cure:
Arthritis, Diverticulosis, Osteoporosis, Obesity, Diabetes, Impotence, Kidney Disease, Strokes, Hypoglycemia, Prostate Cancer, Salmonellosis, Constipation, Peptic Ulcers, Breast Cancer, Colon Cancer, High Blood Pressure, Asthma, Gallstones, Heart Disease, Trichinosis [31]

For more information about the health benefits of a vegan diet, have a look at the Vegetarian Resource Group's nutrition page.

References:
[1] Lester Brown, et al., Vital Signs 1994 (Washington, DC: Worldwatch Institute, 1994), pg. 32.
[2] Robert Repetto "Renewable Resources and Population Growth," Population and Environment 10:4 (Summer 1989) pg. 228-29 cited in Rifkin, Beyond Beef (New York: Dutton Press, 1992).
[3] Ibid., pg. 3.
[4] Ibid., pg. 3.
[5] US Department of Agriculture, Agricultural Statistics 1989; p. 390, table 554, "Crops: Area, Yield, Production and Value, United States, 1986-99" (Washington, DC: GPO, 1989).
[6] Ibid.
[7] Tom Aldridge and Herb Schlubach, "Water Requirements for Food Production," Soil and Water, no. 38 (Fall 1978), University of California Cooperative Extension, 13017; Paul and Anne Ehrlich, Population, Resources, Environment (San Francisco: Freemna, 1972), pg. 75-76.
[8] Ibid., pg. 13-17.
[9] Georg Borgstrom, presentation to the Annual Meeting of the American Association for the Advancement of Science, 1981, cited in John Robbins, Diet for a New America (Walpole, NH: Stillpoint, 1987), pg. 367.
[10] Ibid, pg. 10.
[11] Norman Myers, The Primary Source: Tropical Forests and Our Future, 1992, cited in Brown et al. as per note 7.
[12] Lewis Scott, The Rainforest Book (Venice, CA: The Living Planet Press, 1990).
[13] Lewis Regenstein, How to Survive in America the Poisoned (Herndon, VA: Acropolis Books, 1982), pg. 173.
[14] EPA study cited in USA Today, Sept. 13, 1994.
[15] Rachel's Environment and Health Weekly, #450, July 13, 1995.
[16] "A Brief Review of Selected Environmental Contamination Incidents with a Potential for Health Effects," prepared by the Library of Congress for the Committee on Environment and Public Works, US Senate (Aug 1980), pg. 173-174.
[17] USDA, Economic Research Service, "World Agricultural Supply and Demand Estimates, WASD-256," July 11, 1991, tables 256,-7, -16, -19, -23.
[18] USDA, Economic Research Service, "World Agricultural Supply and Demand Estimates, WASD-256," July 11, 1991, pg. 17.
[19] Amended Petition Requesting the Food and Drug Administration to Halt the Feeding of Ruminant Animal Protein to Ruminants, The Foundation of Economic Trends, Washington, DC, June 3, 1993.
[20] USDA figures as cited in Frances Moore Lappe, op. cit. note 35, pg. 70.
[21] Patricia Allen, "The Human Face of Sustainable Agriculture," Issue Paper No. 4, Nov. 1994, University of California, Santa Cruz, Center for Agroecology and Sustainable Food Systems.
[22] Jean Pennington, Food Values, 15th edition, Perennial Library Press, 1989.
[23] MJ Martin et al, "Serum cholesterol, blood pressure, and mortality, implications from a cohort of 361, 662 men," Lancet 1986; 2:933-6.
[24] S. Moncada, JF Martin, A. Higgs, Symposium on regression of atherosclerosis, European Journal of Clinical Investigation 1993; 23:385-98.
[25] G. Bell, Textbook of Physiology and Biochemistry, 4th ed. Williams and Wilkins, Balentine, 1954, p. 167-170.
[26] National Research Council, Recommended Dietary Allowances, 9th ed., Washington, DC, National Academy of Sciences, 1989.
[27] For complete documentation, refer to: John McDougall, MD and Mary A. McDougall, The McDougall Plan (Piscataway, NJ: New Century, 1983); John McDougall, MD, McDougall's Medicine, A Challenging Second Opinion (Clinton, NJ: New Win Publishing, 1985), 75; John Robbins, Diet for a New America, Walpole, NH: Stillpoint, 1987.
[28] Lappe, Frances Moore, Diet for a Small Planet, tenth anniversary edition, Ballantine Books, New York, 1982. 17, 162.
[29] Phillip Kapleau, To Cherish All Life, Harper and Row, San Francisco, 1981, p. 59.
[30] Ibid.
[31] For complete documentation, refer to: John Robbins, Diet for a New America, Walpole, NH: Stillpoint, 1987; John McDougall, MD and Mary A. McDougall, The McDougall Plan (Piscataway, NJ: New Century, 1983); John McDougall, MD, McDougall's Medicine, A Challenging Second Opinion (Clinton, NJ: New Win Publishing, 1985), 75.

Note - this information is based on research by Earthsave