By definition Vegan means not eating, wearing or using anything that was produced with animal products. The list of non-Vegan products includes honey and beer filtered through fish scales (a common process) among the more obvious beef, lamb and pork entries. Vegetarians use and consume animal products to varying degrees as long as the killing of animals is not involved. For example, consuming dairy products is not something a Vegan would do but a Vegetarian might. There are Lacto-Vegetarians (dairy allowed) and Lacto-Ovo-Vegetarians (dairy and eggs allowed), and Vegetarians that use and wear animal products. The reasons for being Vegan or Vegetarian can be broken down into 4 main groups: health, religion, animal rights/cruelty or sustainability/affordability.
Prohibiting the use of animal products is a very ancient concept. Usually associated with some form of religious observance, abstinence from animal products is a part of many religions around the world. Fasting, meditation and vegetarianism have all been part of many religions' formula for getting closer to God. A Hindu sect carried vegetarianism to its ultimate height by filtering their air and water to keep from ingesting even the smallest of animals. Abstinence from animal products was thought to have a quieting and calming effect so our attention could be directed inwards for meditative and introspective purposes.
There are probably more vegetarians around the world than meat eaters simply because most can't afford to eat meat or its just not available. The vegetarian movement in this country began during the later half of the 19th century with the rise of the Seventh Day Adventists who espoused the health benefits of abstaining from meat, tobacco and alcohol. Upton Sinclair's book The Jungle (1903) painted a grim picture of the newly industrialized meat packing industry and caused a public outcry concerning the quality and safety of the food supply. For many, eating meat became associated with bad health.
The 1960s' counter culture movement saw a resurgence of vegetarianism from a sustainability standpoint. Due to the Green Revolution of the mid 20th century, the resulting population explosion and the continued outbreak of famine in many third world countries, many grew concerned that the planet wouldn't be able to produce enough food to feed everybody. Books published during that time presented the case that more people could be fed if they ate grain rather than feeding the grain to cattle and then eating the meat. It took so many pounds of grain to produce one pound of meat….why not just eat the grain? Frances Moore Lappe's Diet for a Small Planet, using a scientific view point, showed how we could get all our daily nutrition from vegetable sources.
Oriental religions requiring abstinence from meat became popular during this time increasing the call to vegetarianism. The concept of karma (actions in the current life affect subsequent lives) became a part of our culture and influenced a whole generation's concept of life and eating habits. The Macrobiotic movement with its modern interpretation of the ancient Chinese concept of opposing but mutually supportive energies of Yin and Yang also promoted vegetarianism. The ancient Chinese and Hindus, among others, had figured out that eating too many animal products could lead to many illnesses, diseases and death simply because they created too much energy. Many scientific studies over the last forty years have also shown the detrimental effects on some people, cholesterol and heart disease for example, of consuming too many animal products.
Converting to Veganism or Vegetarianism is not for everyone. Everybody's constitution is different and has different energy and nutritional needs. Many people have cured themselves of discomfort and disease by abstaining from animal products while others would have a tough time maintaining their health without them.