There are references in early Syriac Christian texts such as the Liber Graduum to the idea that the Apostles lived on a diet of bread, leaves and herbs. This practice, called* is carried on by some monks in the East.
The very fact that abstaining from meat is considered a work of penance* shows that it is an actively good thing. Penance doesn’t mean making yourself miserable, it means giving up something that, while not sinful, makes you more able to devote yourself to God. You can’t give up praying or give up wearing clothes as penance, because those things won’t bring you closer to God. Thus, while the Church has never condemned meat eating, and neither do I, giving it up from time to time can bring you closer to God. Same is true of alcohol and various other things that are not sinful in themselves.
I’m NOT advocating worshipping the earth or one another, but acknowledging with humility our place in the order of God’s creation.
Jesus, of course, would have eaten meat at the Last Supper, as well as bread and herbs.