From the lankavatara sutra:
Meat, the sinful food, is not permitted according to the three vows: the vows of individual liberation, the Bodhisattva vows and the tantric vows. Thus Buddha stated: "I have never approved, do not approve, and will never approve of a meat diet." He declared: "my followers must never eat meat."
A
Mahayana scripture doesn't lock it from me, but it helps. There are so many reasons for me, but ultimately it just seems unskillful. There's too much accumulation of various arguments.
Many people say, "the Dali Lama eats meat." But when he stopped eating meat again, did they notice? Did that sway them?
Some people say, "but plants have feelings to." But if they really meant that, they would only eat plants, and not meat which involves more killing of plants than plant eating.
I stopped eating meat for the first time when in a nutritional science class, I learned that it was not necessary. Being given free BBQ ribs, my weakness at the time, I went off the bandwagon.
My second stint as a vegetarian was when my good friend went to visit a friend who'd become a butcher, and was revolted. He read a book, I read it, and it convinced me. But I felt into some poverty, and felt I could not pass up free food, even if it had meat, and once the seal was broken, I just ate it. Envirnmentalism began to play a role in my not eating meat, beyond the dietary and more straight ethical questions. I've never really had that visceral reaction to a corpse, but I am repulsed by some of the practices.
My third time trying to be a vegetarian, I made an exception for fish. I thought: They are free range, and I need protein. I wasn't such a good vegetarian, a nutritionist in training examined my diet and said I was over eating carbohydrates because of a lack of protein. I'd restarted it at the example of my new uncle who is a vegan. He was eating a muffin that obviously had eggs in it. I asked him how he reconciled it? He said he wasn't 100% pure, but he aimed for it, and that even if he was out and fell off the wagon, he got back on. I realized, eating meat once didn't mean that I had to abandon my goals. But I read a book called Cod, and learned about the fishing practices. They drag a net through the water, killing everything. Then they call the market, find out what fish is bringing the most money, because they have quotas and can only take so much. And then they push the dead sea life off the deck back into the dead waters. No more illusions about free range fish.
My latest conversion was a combination of FWBO peer pressure (positive in this case) and a deepening feeling about not wanting to eat meat because it just wasn't skillful. One day I summoned the courage and will power and just did it. It was my hardest conversion somehow, maybe because I wasn't playing any more. I would not eat meat any more because of my conviction. I felt ashamed to eat meat. I saw the virtue in Vajramati, Seth and Trebor.