Vegetarian diet is extremely advocated in Dharmic faiths.
In Hinduism, it's a diverse set of idea though many Hindus prefer a strict lacto-vegetarian diet.
Other philosophies such as Jainism and Buddhism too supports it strongly.
But which one is Adharma? Which should be acceptable?
My thought is that eating meat isn't all that bad, in scheme of things. A couple decades ago when I was first contemplating on this, I went with logic of plants have feelings too, and are alive and are clearly raised to be slaughtered strictly for our benefit. I played with that argument for a number of years whenever some high and mighty vegetarian type wished to be all up in my business about my decision to enjoy a good meaty dinner. It still makes a some sense to me.
It's very rare in the last decade or so that I come across anyone that claims righteousness on this whole topic. I consider that a great thing and like that we all have decided it's a personal choice and so acceptable comes down to individual consciousness.
The more I contemplated on it over the years, the more the ideas of this (physical) world being an illusion grew on me, and that it really doesn't matter what my individual consciousness may think is morally right on this topic. I don't fully accept this and will provide counter arguments to my own self to further contemplate, but do think the illusion of the physical existence trumps whatever amounts to righteousness on this (and other) topics.
I do think ideally, a living being is without lack. How that looks in an ideal, perfect order, I'm not 100% sure. But it does seem possible to me to exist as a living being and not have to rely on food for sustaining life. Being told by others (i.e. a doctor) or my own self (via ignorance) that I am (only) a physical being and that to sustain (my) life I must eat, is really just reinforcing conviction in the fundamental belief (or even error) of my identity as a living being. Justifying that I am in a state of lack and need something outside of me to live.
That we have to eat at all, is to me cutting to the chase of this argument.
And that I still desire to be a physical being enjoying a life on this plane of existence means, for me, that given my understanding of physical world as illusion, I'm caught up in minutiae if I really am pausing to reflect on what I'm ingesting and second guessing myself as immoral based solely on what I eat. That some things are inherently good and others inherently bad. With that logic at work, I'm prone to argue its all inherently bad. But given my deeper understandings around forgiveness, then whatever I (or anyone else) choose(s) to eat, it's all good. It's all natural (to this physical existence). And it's all so ultimately trivial in the scheme of things that I may as well find what I most enjoy eating and have fun with the illusion while I still have desire to experience it.