Cats are OBLIGATE carnivores
Meaning they need meat to live. They cannot turn vegetable matter into the vitamins they need to thrive. They will survive on bagged garbage. Like us they will also develop chronic diseases. A major one being diabetes.
It has took me a long time to finally realize that I needed to do something about what I eat, but for years I have been feeding my cats like royalty Meaning they get free range turkey, rabbit, duck, liver and whatever else meaty they beg for. There favorite is popcorn but since I stopped eating it and they can't cook, they deal without it