Lol, my cat eats a diet of chicken, prawns, some beef, and organs like liver, heart, kidney, and brain. He is extremely healthy and does not look his age (13). He started on kibble but we transitioned him to meat because of hairball and general health issues. His teeth are clean and strong, his coat is shiny, and his eyes are clear.
Honestly, cats are predators. They eat meat. Feed a cat mice and you are close to what mine eats. It would be really strange if they were ok eating rice, corn, and brocoli.
My cat only eats grass when he wants to vomit. He will clean himself, get too much hair in his stomach, then yowl to go outside. He then eats grass, vomits, and is chill. When I am more on top of brushing him this happens less, but if I neglect his brushies he needs to purge the hair.