Nutritional science is so biased toward meat eaters... On a plant based diet, it's so difficult to know what to believe.

I cannot tell if high protein is bad for longevity on a vegan diet, or not. Some studies say it's bad for carnies, but is that because they reduce meat consumption, or is it really the protein? And is there a difference between plant and animal protein there? I assume GPT10 will be able to answer these for me