There are 2 sides to this coin:
On one side, I have heard people say that abstaining from meat helps them to be closer to nature, and that it can enhance psychic gifts.
And on the other hand, I have heard the exact same argument for meat. Ancient cultures believed that eating meat helped one to be closer to the animal, and to be part of nature. Some cultures also eat deceased loved ones, as an act of honor.
I'm a vegetarian, once an omnivore, and I haven't noticed any difference in my abilities or connection to magick and nature. Whatever floats your boat.