FACTS:
In general, humans can eat seeds, fruits, vegetables, roots, and many other plant parts. That said, our bodies aren’t able to digest them all completely.
Herbivores like cows, goats, and deer likewise can’t produce cellulase on their own. However, they have friendly gut bacteria that produce it for them — while humans don’t have such gut bacteria (5Trusted Source, 6Trusted Source).
Yet, our bodies produce all of the enzymes, such as protease and lipase, necessary for the breakdown and absorption of meat
Plants don’t provide certain nutrients that animal products do.
One such essential nutrient that you can’t get from plants is vitamin B12, which is necessary for the normal function of the nervous system and the formation of red blood cells (11Trusted Source, 12Trusted Source).
This is why people who follow a diet that excludes all animal products are advised to take vitamin B12 supplements.
Other nutrients, such as creatine, vitamin D3, and omega-3 fatty acids like docosahexaenoic acid (DHA), are also missing in a plant-based diet. Yet, your body can produce them in small amounts, so you don’t need to rely solely on your diet to obtain them.
Keep in mind that vegan and vegetarian diets should be properly planned to avoid nutrient deficiencies. Other nutrients that may be difficult to obtain on such diets include protein, iodine, zinc, and calcium.
Nothing wrong with being a vegetarian or a vegan, but if you are trying to convince me it is more natural, you are barking up the wrong tree. Biology does not support your claim. It is a poor argument. Do you have an argument outside basic biology?
Sorry I should have cited the source - There is a whole lot more: Should Humans Eat Meat? Biology, Nutrition, and Culture
I’m not putting down vegetarianism or veganism. Just saying, if you are trying to make a biological case for it, you are going to fail.