I found this interesting article in PFA (People For Animals) website http://www.peopleforanimalsindia.org/5-reasons-to-be-vegetarian.html
1) The RELIGIOUS reason
Every religion from Hinduism and Buddhism to Islam and Christianity teaches compassion to all living beings. Animals were created for the same reason as humans, to live. Not to be killed and eaten. As Mahatma Gandhi said , "It ill becomes us to invoke in our daily prayers the blessings of a compassionate God if we in turn will not practice elementary compassion towards our fellow creatures".
2) The KARMIC reason
All our actions including our choice of food have karmic consequences. According to the law of karma, if we cause pain and suffering to other living beings, we must endure pain and suffering in return, both individually and collectively. We reap what we sow, in this life and the next, for nature has her own justice. By involving oneself in the cycle of inflicting injury, pain and death by eating other creatures, one will in the future, experience their suffering in equal measure.
3) The SPIRITUAL reason
Food is the source of the body's chemistry, and what we ingest affects our consciousness, emotions and experiential patterns. If one wants to live in higher consciousness, in peace and happiness and love, then one cannot eat meat, fish, fowl or eggs. The methods used in large modern farms to raise and kill animals causes them immense pain and terror. They are given hormones and antibiotics which biochemists have confirmed end up in and influence the body of those who consume meat. In a very real way, we are ingesting the powerful chemical components of fear, and rage. Absorbing these contributes to a violent mentality perpetuating the cycle of cruelty and confusion. If children are raised as vegetarians, every day they are exposed to non-injury as a principle of peace and compassion. Every day they are growing up, they are remembering and being reminded to not kill. When you won't kill another creature to feed yourself, you will be much less likely to injure anybody at all.
4) The HEALTH reason
Medical studies prove that a vegetarian diet is easier to digest, provides a wider range of nutrients and imposes fewer burdens and impurities on the body. Meat eating women have a 3.6 times higher risk of breast cancer while meat eating men have a 3.8 times higher risk of prostrate cancer. Vegetarians are less susceptible to all the major diseases that afflict contemporary humanity, and live longer, healthier, more productive lives. They have fewer physical complaints, less frequent visits to the doctor, fewer dental problems and smaller medical bills. Their immune system is stronger, their bodies are purer, more refined and their skin more beautiful.
5) The ECOLOGICAL reason
Planet earth is suffering. In large measure, the escalating loss of species, destruction of rain forests , loss of topsoil and the increase in water and air pollution have all been traced to the single fact of meat in the human diet. Meat is the single greatest reason for deforestation worldwide with 55sq ft of tropical rain forest consumed to produce every quarter-pounder hamburger. A major contributor to global warming is methane produced by animals multiplied for meat. With over 6 billion people grazing the earth today, the future of life on earth rests on our choice of food. No single decision that we can make as individuals or as a race can have such a dramatic effect on the improvement of our planetary ecology as the decision to cut out meat. Many seeking to save the planet for future generations have made this decision for this reason and this reason alone. The earth does not belong to man, man belongs to the earth. Whatever happens to the earth will happen to the children of the earth. This we know. All things are connected like the blood that unites one family.
