Excerpts from Supreme Master Ching Hai’s Lecture:
The Buddha concluded that the cause of war is the lack of sharing between people and the greed within us; someone who likes to take too much and leaves none for others. So nowadays in the modern times, people, the scientists, they have made some research and they thought the cause of war may be starvation; many countries starve and many countries have too much, things like that, but not really. We don't really have too much. We just use it wrongly and wastefully.
So they made a research. For example, someone told me in Toronto, he had a restaurant. He had a vegetarian restaurant and a vegetarian magazine; he told me that according to research, if in northern America each person ate a vegetarian meal once a week only, then we would have enough food to feed sixteen million people a year. And then I was startled and said, ""How could it be?" But they worked out that way, not because of the food; it's so many concerning with food, yes. Because the land had to be cultivated and now it's wasted for the cows’ feeding, and all the water supply, all the medicine for the cows, pigs or whatever, and all the transportation.
Everything concerned with the meat diet has reportedly wasted a lot of human substances and that is the cause of starvation of many countries. It takes a lot of food, of protein, medicine, transportation and water to feed the cows, and these things come from underdeveloped countries, too. This protein and food could have been fed and could have been distributed in a different way in order to feed the whole world instead of feeding the cows, and we eat the cows, the secondhand stuff anyhow.
So nowadays many people believe that the vegetarian diet can save the world and minimize a lot of war, and I think I do not oppose this idea. Maybe in the future, very near future, we should try at least to see how it works and then we can comment. But I believe it will work, provided each of us support and try to cooperate.