This belief came about after contrasting the condition of house cats with feral cats who have access to adequate prey. These feral cats are simply magnificent, with strong teeth and gums, thick shiny fur, clear eyes, and well-developed muscles. So while I don't believe our commercially-fed house cats CAN he as healthy as cats eating the diet Mother Nature designed for them, there are ways we can improve their nutrition to minimize health problems. I suggest ground raw turkey, frozen and then thawed to kill some important parasites. Offer an ice cream scoop-sized portion at least twice a week in place of the cat's normal meal.
Some cats refuse raw meat at first, as it is the nature of the cat to distrust strange food.
Let the cat miss a meal or two and get really hungry. Once they start eating raw meat, they love it and feel much better afterward because they are getting what their body really needs without any added preservatives or chemicals. Feed a variety of commercial brands. No commercial food is perfect, as it is impossible to duplicate the natural diet in processed cooked form. Feed one brand for a few weeks, then switch to another brand.