Ancient monks just didn't eat "meat", not meat, because there was still a big difference between meat and meat. The folk prescription of meat is grass prefix, which represents a plant. In fact, it refers to some plants with pungent smell, such as leeks, garlic, green onions and leeks. Because eating these things in your mouth will produce a great smell and it will be unsightly to speak. Moreover, Buddhism believes that having such a smell in the mouth is disrespectful to all beings and to the Buddha, so not only monks don't eat meat, but even many people in the upper class don't eat meat for image.
So at that time, it was said that monks could not eat meat, only that they could not eat vegetables with special smells. The fishy smell refers to the fish, duck, chicken and mutton that we usually think of. Buddhists are philanthropic and cannot kill. Therefore, Buddhist disciples are self-disciplined not to eat stimulating foods such as onions, ginger, garlic, and leeks, because leeks have an aphrodisiac effect and will affect the cultivation of their families.
As for the rule that monks can't eat meat, it was put forward by ancient Liang Wudi. Before being ordained, Liang Wudi once issued an imperial edict: monks and monks were strictly forbidden to eat meat under any circumstances. Besides, he made it himself. He insists on eating only one meal a day, mainly bean soup rice, without greasy meat, which is very simple. Even he changed his style of being addicted to women and interrupted sexual intercourse. Since the age of 50, he has never been lucky for any woman.