I. It is important to differentiate as to the reason why certain of our sages past and present chose to be vegetarians, and the reason may be far different than just moral repugnancy. The Divrei Moshe on Parashas Noach brings down the following in the name of the holy Arizal: "The reason that our sages said that it is forbidden for an ignoramus (am ha'aretz) to eat meat, is because an ignoramous does not have the ability to clarify the sparks (of holiness contained within the animal), and on the contrary, he removes very little holiness contained within and is drawn after the (coarseness and lack of refinement of the) animal." I would suggest that it is based upon this reason that some talmidei chachamim and Chasidim choose not to eat meat. By the same token, one who goes to a prominent Chasidic rebbe's tish will always notice the care and concentration that the apply to the eating of all of their food, meat included, in order to "clarify the sparks" as spoken of above. ( If anyone would like me to elaborate on this concept, feel free to ask.
II. I strongly recommend reading "The Vegetarian Myth" by Lierre Keith, and published by the Price Pottenger foundation, based upon the remarkable research by the late Drs. Weston Price and Francis Pottenger. I merely present this information without opinion or comment for your edification: Here are some of the myths that are discussed in this and other writing published by Price Pottenger: 1. Meat consumption contributes to famine and depletes the Earth's natural resources. 2. Vitamin B12 can be obtained from plant sources 3. The body's need for vitamin A can be met by plant foods. Vitamin D can be obtained by exposure to sunlight 4. Meat eaters have higher rates of heart and kidney disease, cancer, obesity, and osteoporosis than vegetarians. 5. Saturated fats cause heart disease and cancer, and low-fat, low-cholesterol diets are healthier. 6. Vegetarians live longer and have more energy and endurance than meat eaters. 7. The 'Caveman' diet was low fat and/or vegetarian 8. Saturated fat consumption has increased in the 'developed' world in the 20th century, with a corresponding increase in heart disease and cancer. 9. Soya products are adequate substitutes for meat and dairy products. 10. The human body is not designed for meat consumption. 11. Animal products contain harmful toxins. 12. Eating meat or animal products is less 'spiritual' than eating only plant foods. (again refer to point #1 above concerning "sparks").
III. As a physician and practitioner of traditional Jewish and Chinese medicine, we never take the "one shoe fits all" approach to food or medicines, for that matter. Just as there is no such thing as a panacea, so too there is no hard and fast rule about diet for everyone. Instead we take the approach that there is only one absolute, and that is the A-lmighty. Everything and everyone else in the created world is relative, and based upon the constitution and status of each patient, the appropriate diet and if necessary medicinal formula should be prescribed. And this is not only true of Chinese medicine, but in multiple places the Rambam brings down that one should eat foods based upon the persons constitution and temperament. As such, for someone who is in a state of repletion or excess, I would have no problem with them going on a vegan diet (but just to allow them to get in balance, which may take 3-6 month, or perhaps longer, but certainly not indefinitely). But I have to tell you, that virtually ALL vegans that I have treated present with severe Liver Blood, Kidney Yin and Kidney Jing vacuities (deficiencies). One can do what they want for whatever moral reason that they choose for themselves, but in our stressful and polluted world, I don't believe that it is prudent or wise to choose to be a vegan. As Jews, our decisions should always be based upon how we can best please our Maker and Father, The Holy One, Blessed Be He, and in all cases, this one included, I would contend that decision should never be based upon our own subjective prejudices, but rather how we can best serve him. The Rambam says in Hilchos Dayos, that each of us should direct our hearts and thoughts to know Ha-Shem, and it is impossible to know Ha-Shem if one is sick, hungry or in pain. I would humbly add to that list someone who is out of balance.
Tomorrow night is Tisha B'av. May we merit seeing the Bais Hamikrash rebuilt. Our sages tell us that at that time, "knowledge of G-d will fill the world as water fills the seas." I don't think that it's for us to debate what will be then in terms of what the nature of the korbonos will be, but we sure will know much more than we do now!
Saving 
Thank you for your thoughtful comments. Two observations: 1. It is not clear that the messianic era will be vegetarian. I am familiar with Rav Kook, ZT"L's opinion, however, it is a singular opinion,as many other scholars and chasidic and Kabalistic masters apply the verse figuratively, and, as I stated in my article, we just won't know until the time comes, will we. Second, if you read my comments carefully, the opinions expressed in point two, are not mine, but rat
For further information about Jewish teachings on vegetarianism, please see my over 140 articles and 25 podcasts and
JVNA argues that meat consumption and the ways in which meat is produced today conflict with Judaism in at least six important areas:
1. While Judaism mandates that people should be very careful about preserving their health and their lives, numerous scientific studies have linked animal-based diets directly to heart disease, stroke, many for