I have been omnivore, lacto-ovo vegetarian and vegan for different time periods so I can compare in my own experience. Being vegan was absolutely the cleanest spiritually - hands down, no question, my sensitivity to energy sky rocketed and I could meditate easily and more deeply. Vegetarian similar but less so. Eating meat for me weighs down my energy and if I eat meat (or dairy or eggs) that came from factory farming where the animal suffered in life as well as death I can absolutely feel the difference. It is worth the money to buy free-range eggs/meat if you can because the energies contained in our modern factory farmed animals' meat is awful, because their lives are horrible. It is truly shocking how much needless suffering is inflicted on these animals just for greater profit.

So even outside of the moral question of whether one should eat meat at all, those are the effects I feel. Many years ago I spontaneously stopped eating beef and I suspect it was because of these effects. I guess if you wanted to eat in the highest form possible with injury to none fruits and nuts & seeds would be the way to go. No plant has to die for those but I'm not sure how healthy it would be for the body.