It's not really debatable for folks that seriously look into the externalities associated with the indutsrial farming of livestock. It's an incredibly wasteful and polluting industry. The production of livestock accounts for more global greenhouse gas emissions than transportation.
Yeah, look seriously into how many animals die in fields, how many poisons are in waters, in soil, because of agriculture, how many birds die because of it, how insects and bees are dying out, how air is worsening, dusty, children are getting asthma and allergies, living near fields etc.
The landscape of countryside is ugly, destroyed by this basically dead land, animals have nothing to eat and nowhere to hide. Just unending fields of plowed land, everywhere one looks. Also the soil is getting so depleted, that tons of chemicals must be used for another run the next year. Its not sustainable at all.
I follow the World Health Organization guidelines for recommended nutrient intake. This is achievable on a plant-based diet for most of the world's population.
I eat 3-4 servings of legumes every day, 3-4 servings of grains like whole grain rice, barley, or farro, 3-5 vegetables like bell pepper, tomatoes, potatoes, sweet potatoes, carrots, and 2 servings of brassicans like kale, cabbage, or broccoli. I also use some oil, seeds, nuts, yeast, mushrooms, seaweed and aquatic plants as well, in small amounts. I have fruit as desert or snacks at least once a day. Every few days I also take a B-12 supplement, though most of my B-12 is from actual food. I've been eating this way for three years now and my blood lipids (cholesterol and triglycerides) are excellent, the lowest they have been in my entire life (I was a vegetarian when younger, but my lipids were not as good, because I ate alot of dairy).
And who told you 3-4 servings of legumes, of grains, what vegetables exactly, in what proportion? How do you know it covers human nutrition, in this combination?
Its like 30 things you are mixing together. It must be very complicated to know why, when and how. So how do you know? Do you study botany, to know what allergens, poisons, anti-nutrients and nutrients are in what plant and how to combine all of them to simulate meat?
Vegans can go as long as 5 years until all the vitamins stored in liver get depleted. Then the health becomes going downhill quite quickly for many of them. Until that, the diet looks easy, but it runs on savings.
Also, maybe I am mistaken, but did you not write in some other thread that you are obese? Which would be a strange thing if you are 3 years on an ideal human diet.