It could screw up the cats digestive system if you feed it different types of food.
Also dry cat food is a death sentence for cats... most of the time. It's full of carbs and pretty much the worst thing you can feed em. For a cheap wet alternative I'd suggest Fancy Feast (or generic) and only the flaked kind. Full of protien. Give the kitty 1/2 a can every 12 hours.. and perhaps some snuggles.
