Reading Food Labels
Most brand name and premium cat foods will contain all the nutrients that your cat needs, but you should always take a moment to read through all the ingredients listed on the package. Quality food will contain at least 4 percent taurine, an essential amino acid that should always be included in your cat's diet. Cats that do not get enough taurine can have severe eye problems, which may eventually lead to blindness.
Quality foods will not be filled with sugar, food dyes, or preservatives. Another good clue is for a bag of food to have the phrase "meets the nutritional levels for a complete diet" or "provides complete and balanced nutrition as established by the Association of American Feed Control Officials" printed on the bag.