>>10893602>Shukr-Acharya (Guru of Rakshas) first restricted consumption of meat and alcohol for brahmans after he was forced to resurrect one person (son of Brahaspati, I think), whom he had eaten under influence of alcohol and had to teach him about the art of resurrection so that he can, in turn, resurrect Shukr-Acharaya.Manu Smriti includes meat (prepared without spices) among Havi (i.e. food that are fit to be offered in Vedic sacrifices).
3.257. The food eaten by hermits in the forest, milk, Soma-juice, meat which is not prepared (with spices), and salt unprepared by art, are called, on account of their nature, sacrificial food.
A Brahmin can meat under certain circumstances, and he has to only consume the meat that has been duly sprinkled with mantra-infused water.
5.27. One may eat meat when it has been sprinkled with water, while Mantras were recited, when Brahmanas desire, in the performance of a rite according to the law, and when one’s life is in danger.
Only the meat that has been first offered in an animal sacrifice is however considered fit to be eaten.
4.27. A Brahmana, who keeps sacred fires, shall, if he desires to live long, not eat new grain or meat, without having offered the (Agrayana) Ishti with new grain and an animal-(sacrifice).
4.112. While lying on a bed, while his feet are raised (on a bench), while he sits on his hams with a cloth tied round his knees, let him not study, nor when he has eaten meat or food given by a person impure on account of a birth or a death,
A Brahmin can not refuse eating meat in certain circumstances too, like in funeral ceremonies (Shraddhas).
And, a Brahmin becomes degraded if he chose not to eat meat, during the time when he is conducting a Vedic sacrifice.
Vyasa Smriti:
A Brahmana, engaged in the celebration of a religious sacrifice, becomes degraded by not taking meat.
A Kshatriya should eat the cooked flesh of a quarry after Jiaving propitiated therewith the gods and his departed manes.