I am often asked whether lay persons must adopt a completely vegetarian diet to be considered persons of Dharma.
One should not conceive of there being any sort of doctrinal imperative about this matter. A completely vegetarian diet is not required of persons of Dharma (though it is certainly set out as an ideal to which all should aspire).
When we have realized shinjin, and as Buddha-Nature (Amida) gradually permeates our being, we may gradually and quite naturally notice a decrease in our desire to consume the flesh of animals as food. However, being that compassion is the basis for abstention from meat-eating, it would be somewhat hypocritical to then exhibit a lack of compassion for those who find it difficult to change a long-established and culturally reinforced habit.
Forcing oneself to be vegetarian is willful, dangerous and counter-productive. As in most things, it were well for persons of Dharma to adopt the middle path between the extremes and permit the gradual dissolution of such passions without the egotism of self-power calculation and ego-driven practice.
See wikipedia:Buddhist vegetarianism for more information on this controversial subject.