Not just animals but plants have life too. So if you think you are doing a great justice to non-violence by being vegetarian then you are dead wrong. There is a concept of something called food-chain that has kept the circle of life going since the Paleozoic Era. In the current era, plants and animals (including human beings) have to depend upon one another for food. That's how the check and balance for sustainability of any form of life is maintained.

Whether vegetarian or non-vegetarian, we are destroying the life of a plant or animal unless we start feeding upon lifeless mud or stones!

One can still be kind or responsible to both sources of food by minimizing the plight of both animals and plants. For instance, as a human being one can refrain from taking away the life of a plant or animal if he/she never had an intention of turning into some form of food or utility in the first place.