We are biologically herbivores. We cannot digest raw meat and we have to flavour it to make it appealing. Our digestion system, jaw, and other features are those of a herbivore, and we develop atherosclerosis from eating too much fat, unlike any non-herbivores.
Plant based diet has been proven to slow and even reverse cancer, but there's no money in it. It will take time but slowly doctors are beginning to acknowledge that our biggest killers are the result of what you put in your body.
This is ignoring the real issue which is animal agriculture. If we ate the corn ourselves instead of feeding it to cows, we'd be using much less land, be healthier and of course, end the worst crime in history.
I highly recommend watching the documentary 'Cowspiracy'.
You don't need complete protein, only the 8 amino acids that our bodies can't synthesize. Any plant food contains more than enough of those amino acids.