How you approach a christian argument for vegetarianism depends a lot on your approach to theology.

Some people argue that there is nothing in the bible which says we should not eat meat, and therefore we are free to do so if we wish. I think this is a flawed view, for a number of reasons.

To begin with, the bible is an historical document, and has to be viewed in the context of the changes that have occurred in our ways of life in the thousands of years between when it was written and now. This is not at all to say it is wrong, only that we need to look very closely to discern the true message under the surface.