The sacrifice of the Purusha as described in the Purusha Sukta of the Rig Veda as well as the sacrifice of the Divine Mother as described in the Devi Suktam are an indication of the thread of oneness and the deep interconnectedness of all that seems separate. It means that the sense of separateness and the assertion of a separate life which leads to the devouring of other lives ends up by a rebound from All-life in a way that the eater eating himself is eaten.
Yes annam refers to food as well as all this material existence which is constantly being devoured by Time and brought forth again. One of its practical implication is that no life can support itself in isolation or by excluding others. It is a reminder to serve as a corrective to our excess egoism. Secondly it means that the whole universe is being recreated at each moment and, if we will, we can take advantage of this and recreate ourselves each minute.
Affectionately,
Alok Da