In Krishna consciousness meat eating (including eggs) is prohibited. This is on the grounds of compassion to other living beings and also Krishna does not eat flesh of animals. So if Krishna does not eat, then we do not eat. This is the idea. Personally, for me it made sense instantaneously and I did not need any further explanation on why one should become vegetarians.
I, however, wanted to know if there were any direct scriptural references on the abominable practice of meat eating. Below is a conversation piece by the supreme devotee of God - Narada Muni.
Nārada Muni said: Among all the attractions of material enjoyment, the attraction of riches bewilders one's intelligence more than having beautiful bodily features, taking birth in an aristocratic family, and being learned. When one is uneducated but falsely puffed up by wealth, the result is that one engages his wealth in enjoying wine, women and gambling. Unable to control their senses, rascals who are falsely proud of their riches or their birth in aristocratic families are so cruel that to maintain their perishable bodies, which they think will never grow old or die, they kill poor animals without mercy. Sometimes they kill animals merely to enjoy an excursion. While living one may be proud of one's body, thinking oneself a very big man, minister, president or even demigod, but whatever one may be, after death this body will turn either into worms, into stool or into ashes. If one kills poor animals to satisfy the temporary whims of this body, one does not know that he will suffer in his next birth, for such a sinful miscreant must go to hell and suffer the results of his actions. While alive, does this body belong to its employer, to the self, to the father, the mother, or the mother's father? Does it belong to the person who takes it away by force, to the slave master who purchases it, or to the sons who burn it in the fire? Or, if the body is not burned, does it belong to the dogs that eat it? Among the many possible claimants, who is the rightful claimant? Not to ascertain this but instead to maintain the body by sinful activities is not good. This body, after all, is produced by the unmanifested nature and again annihilated and merged in the natural elements. Therefore, it is the common property of everyone. Under the circumstances, who but a rascal claims this property as his own and while maintaining it commits such sinful activities as killing animals just to satisfy his whims? Unless one is a rascal, one cannot commit such sinful activities. Atheistic fools and rascals who are very much proud of wealth fail to see things as they are. Therefore, returning them to poverty is the proper ointment for their eyes so they may see things as they are.
- SB 10.10-8-12
In the above conversation Narada muni describes how it is such a bad habit to engage in meat eating and because of that they will suffer in their next lives. Narada muni talks about returning to poverty. In this context, poverty does not necessarily mean economic poverty it can also mean degradation in terms of one’s bodily functions like taking the body of a plant or animal etc. Devolving into lower species of life is the greatest punishment as the living entity (spirit soul) will suffer immensely in lower species of life. It is the responsibility of human beings to evolve into higher forms and not devolve!
So my humble request to meat eaters is that eating meat may taste nice at that moment but it does come with heavy consequences. Beware!