namaskaram vishvavajra ji
Different branches of Buddhism answer this question differently. The Theravada answer tends to be that monks can eat meat as long as it's somebody else's leftovers, and there's no explicit rule for laymen. The standard Mahayana answer, especially in the Chinese tradition, is that everybody ought to be vegetarian, including laymen. But even then it's more of a strong recommendation than a rule; nobody is actually going around policing what people eat. It's a decision people have to come to on their own.
jai jai , ....by this explanation it can be plainly seen that as Buddhism developed and gained strength where it went into new comunities it actively taught on the principle of non harming , Mahayana traditions also set up monastaries , therefore a need to provide for resident monks , in which case a standard would have been set prohibiting meat in the diet in all places except where there is simply not enough food to live in a meat free diet , (this happens in some areas like mongolia and tibet) once established monastaries became more prevailant there was more possibility to influence the local comunities .
All strands of Buddhism agree that intentionally killing sentient beings for food is a bad idea and an obstacle to one's practice, as is participating in that kind of thing by purchasing meat (i.e. paying someone else to do the butchering for you). Where the traditions differ is on whether it's OK for mendicants to accept leftover meat that is donated by someone else. Meat-eating of the sort that is familiar to most people today is strongly discouraged all around as something that interferes with the cultivation of compassion etc.
personaly I dont think we should even see it as an obstacal to ones own practice , more we should regard it as an offence to cause suffering , ....true yes it is an obstacal but only where that obstacal is attatchment , ...there by one might say that such an attatchment will certainly result in an interferance with ones cultivation of compassion , as one canot have selective compassion , ....except at the begining of ones life where one naturaly in a child like manner feels compassion for a dog otr a cat , but will happily eat a Calf or a Goat when one matures one realises that a dog and a goat have the same sentient nature , when one comes to this realisation one can no more eat a goat than one can ones pet dog , ....
although the cultivation of compassion is seen as a worthy practice , ....it is more a practice of overcoming the tendancy of the mind to see the self in one light and others in another , ...thus by the practice of equalising self and other compassion naturaly arrises , ...
Consequently, although not all Buddhists are vegetarians in practice, Buddhism and vegetarianism are practically synonymous in many places, so strong is the correlation. But you don't have to be a vegetarian before you can start practicing Buddhism—quite the contrary! In my experience, people are often not vegetarians when they first start practicing, but steady practice will make them want to give up their carnivorous ways in time as they come to understand the consequences of their actions.
this is very true of the mahayana traditions where the empasiss on compassion is more prominent , but sadly many more theravadins continue in the diet of their culture they may prehaps lesen their intake , .... but from observation the question of meat eating is not given so much consideration .[