A brilliant device in the film District 9 is that the overgrown walking-erect shrimps (who have invade Earth and are quarantined in District 9) are addicted to cat food. It is brilliant because it makes sense: of course cat food would be addictive to any animal that would eat it.
My cat is now old enough and spoiled enough that she has a preferred packaged cat food that is marketed as a “snack.” She will stalk away from “normal” cat food.
Are you old enough to remember or have you seen a YouTube video in which doctors advertise cigarettes as “healthy.” (If you haven’t seen the first half hour of Sleeper, by the way, I strongly recommend it. If you have seen it, watch it again; it will make you smile.) Is it any wonder that our pets become addicted to particular products? Obviously it’s not the FDA’s (Food and Drug Administration) concern. So god knows what they put in cat food, but mine becomes finickier and finickier every day when it comes to eating “ordinary” cat food.