Another thing to add, is that just picking up pieces of human grade meat isn't enough for cats, you need to be feeding them products with high amounts such as hearts and even then they recommend taurine supplements. The fact of the matter is for a cat to get enough amino acids from meat they need to be eating whole corpses of small animals and nothing else, because the meat you buy from stores will be one part you have to constantly be buying different parts and mixes to attempt to get all the animal amino acids and even then they will probably still recommend a taurine supplement.
Lets also talk about the natural diet, cat and dogs descendent's ate meat in the wild but when we get to domestication for thousands of years they've been living on human scraps and i doubt that had enough of the animal amino acids yet they continued to survive for years. After that came commercial pet foods, which when processed provided little amino acids so cat's were deficient for years until they discovered that they needed animal acids like taurine and cobalamin so they started putting in synthetic and that's where they are at today.
The fact is vegan pet food gets a bad rap when the exact supplements are used in commercial pet food, which is further backed up by the above study. So a few conclusions can be drawn from all this, a common ancestors natural diet isn't the same as an domesticated animal, vegan pet food contains the same amounts of amino acids as commercial since they both use synthetic sources, to have a cat with those acids from meat would require them to be only eating small animals whole so they can receive all the nutrients from various body parts which would be destructive of natural wildlife and finally we can see from all these facts that there is nothing wrong with vegan pet food since cat's and dog's have lost their natural diets and can live fine on a vegan diet(as seen in the above study).
My point of this post isn't to argue all animals should be on a vegan diet, it's to provide the facts about a non-animal diet for pets after researching the idea with a un-biased approach seeing as i have neither of these animals and wanted to know the facts for myself. On the research against, i mostly found information about the impacts of amino acid deficiently which didn't take into account artificial supplements and the fact that commercial pet foods also use these supplements.
Please try to read this with an open mind and don't take it defensively

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