Vegetarians are two main types: those who include some animal products in their diet and those who do not. Usually the first is called vegetarian and the other is vegan. Vegetarians refer to these diets, but more importantly, to a belief system that supports vegan practice. Ironically, not all vegetarians subscribe to such a belief system. They may not like the taste of meat, for example, but most of them, especially vegetarians, have a view that prohibits eating animals. Many people today, whether vegetarian or not, realize that livestock production, especially through large-scale intensive or factory farming, causes the worst of animal abuse and is a very wasteful way of securing food.

There have been vegetarians throughout recorded history. Their food choices are often seen as either subversive or cranky, but their voices, although in the minority, are rarely heard by conscientious people. In what follows, a number of arguments that can often contribute to the vegan attitude will be summarized.

1. Health. Whether a vegetarian diet is healthy or healthier than a diet that includes meat is controversial. It may seem that good health is simply a matter of one’s long-term self-interest, but some philosophers, particularly Immanuel Kant, have argued that we have duties to ourselves, and others like Aristotle have argued that we should always strive to achieve some kind of virtuous or morally commendable life. In both of these perspectives, health, and thus a healthy diet, will be a precondition for us being able to carry out any moral obligations, including our duties to ourselves and to act virtuous, and thus in itself is a matter of moral concern. People for whom we have responsibilities likewise have a stake in our health, as does society, which has an interest in being productive and non-stressful members. If a vegetarian diet is generally healthier, vegetarians assert, then it will be the one we should choose for both our self-esteem and our concern for others.
   
2.  The animal’s suffering and death. There is no way to raise animals that are fed without pain and suffering, and whatever happens, death is the fate of the animals. Confinement, transportation, and slaughter are the main sources of abuse in the process of extracting consumer products from animals. Factory farming, a common phenomenon of our time, exacerbates problems, and their severity is well documented. Utilitarians are usually concerned with enhancing the pleasure and other interests of conscious beings, and by reducing or eliminating pain, suffering, and other conditions that frustrate their well-being. Vegetarian diets help achieve these desired results. Animal rights theorists argue that many animals are indispensable individuals with important moral interests and thus rights, including the right to live and not to cause undue pain and suffering. From this point of view, even a completely painless meat production that pleased human eater and thus would satisfy utilitarian ethical demands, would still be unacceptable, since death is the ultimate harm to rights holders.
3.  Impartiality and moral well-being. A neutral person who is well-acquainted with animals realizes that they have important moral concerns, such as survival and enjoyment of some well-being, health and satisfaction that can only be respected if we abstain from eating them. The use of animals as foodstuff violates the state of neutrality and shows the distinction between species.
4.  Environmental concerns. Large-scale meat production by agribusiness is causing significant environmental depletion and degradation, including massive demand for water supplies and fossil fuels, deforestation, desertification, loss of wildlife habitats, greenhouse gas pumping, and waste flows into waterways. The global shift to vegetarian diets is seen as a way to reduce or eliminate these effects, and as a necessity in light of the unsustainability of the meat economy.
5.  Global hunger and social justice. Animal food production that relies on feeding the animals in the feedlot rather than leaving it natural forage is highly wasted, resulting in much less protein than the protein input required to make it successful. Plant-based diets will help free up resources to feed the world’s hungry by undermining an artificial economy of scarcity.
6.  Forms of persecution overlap. Some ecofeminists have argued that the different forms of domination, oppression and exploitation are causally and conceptually intertwined. Those who are stronger than others tend to exercise control over them, view them as inferior, and treat them as merely serving their own interests. The plant way of life can contribute to breaking this traditional pattern by altering the dynamics of food production, distribution and consumption.
7.  Universality of compassion and kinship. Evolutionary considerations of biological kinship reinforce the idea that humans should exert empathy toward other animals. Vegetarianism is consistent with Com’s passionate approach to life.
8.  Global Nonviolence (ahimsa). Mohandas Gandhi taught that violence begets more violence, that non-violence (or ahimsa) is a supreme moral force, and that humans have a duty to avoid causing harm to other living beings whenever possible, and to reduce it when it cannot be avoided. A vegetarian diet reduces harm to non-human people.
9.  Religious considerations. Some religions, notably Jainism, Hinduism, and the worship of Pythagoras in ancient Greece, shared a belief in reincarnation and the rape of humans and non-human animals. The Pythagoreans believed that animals may contain souls of former humans and therefore should not be eaten. Many Hindus, Jains and Buddhists refrain from eating animals out of respect for tribal beings with spirits. Vegetarianism is sometimes advocated in favor of abstinence or spiritual cleansing. Some Jewish and Christian thinkers have taught that God granted humans agency rather than control over nature. Islam has also been presented as a religion of guardianship, with the stronger condition that causing serious harm to nature is a direct insult to God. Vegetarianism may be seen as essential to the task of supervision. Finally, both the Buddhist tradition and wisdom of indigenous peoples teach that spiritual identity and unity connect all living beings. Although this principle often implies that animals should be killed only out of necessity and respect and without waste, it is sometimes issued in the prescription for a vegetarian or semi-vegetarian diet.