When I nourish myself, I am always eating a being which I have killed or which I have at least prevented from living. I eat an animal which has been killed for me, my life being preferred to its life. I eat something which would have engendered life or sustained the life of another living being: the egg which contained a life in germ, milk (and its derivatives) which were meant to assure the growth of a young animal, vegetables and fruit, the grain of wheat which was a seed. Thus to ensure my life and my survival, I must take or threaten the life of another being. I must induce death. I nourish myself with a life sacrificed for me.
In every act of nourishment there is therefore presence of life and death, a struggle for life against the danger of death, theft, or gift of a life sacrificed in order to permit another to have life and to have it abundantly. The application of this to the Eucharist is evident: In receiving the consecrated bread and wine I nourish myself with the life of the wheat and the grapes sacrificed for me, but also with the Body of Christ given for me and with His Blood shed for me.
Philippe Rouillard, Human Meal to Christian Eucharist
Locus Communis 