Q: Does Judaism encourage vegetarianism?
A: Our great Sages made a point to eat meat in order to sharpen their minds. Nonetheless, great rabbis, including Rabbi Avraham Yitzchak Hakohen Kook, wrote that in the era of Mashiach, may he arrive speedily in our days, we will be strictly vegetarian. The eating of meat is connected only to the service in the Temple. The eating of meat outside the confines of Temple service was permitted when the person was distant from the Temple.
When the Temple is rebuilt, we will all approach this way of life. According to Kabbalah, there are those who eat meat only on Shabbat. There were also many tzaddikim in the recent past who were vegetarian.
The question of health is very important. However, it is not clear that eating meat (in reasonable amounts) is detrimental to one’s health in most cases.
As a rule, we cannot forbid something that the Torah allows. If it becomes clear that the issue in question is detrimental to health, causes wars, or the like, it is possible to suggest to separate oneself from that issue or item or to partake of it only minimally. However, we cannot make a blanket statement to forbid it.
Furthermore, with regard to meat, it is a mitzvah to make the Shabbat pleasurable by eating meat and fish. (This applies to those individuals who derive pleasure from this fare. )