There are 2 main ingredients that are essential in your cat’s diet: 1. Meat 2. Water
1.Cats are obligate carnivores
. This means that cats must eat a diet that is about 85% meat or they will not get the nutrients that they need. Certain nutrients that are found in meat meat can be synthesized internally by other species such as humans and even dogs, but not by cats. For example, taurine is an essential amino acid that cats must have or can develop heart disease along with vision problems, poor coats, and low energy.
Nutrients such as taurine can be chemically synthesized and added into commercial diets, but there are many benefits to feed it from a natural source. Every nutrient found in nature comes with ‘hidden’ benefits that aid its digestion, absolution, and utilization. Chemical reproductions of nutrients may not be as compatible with your cat’s physiology and some of the benefits may be lost in the processing of the diet.
2. Cats should eat a diet that is 70% water and will likely be healthiest when they get moisture from their 
food rather than drinking it from a bowl. Why? Cats were originally desert animals, and there was not a lot of water around to drink. Many cats, therefore, do not have a big enough thirst drive to drink what their body needs, especially if they are eating a kibble-type diet, which are typically about 10% moisture. When eating a kibble diet, a cat must drink enough to make up for the moisture lacking in the food, along with some extra to meet their metabolic demands. Many cats end up with kidney and bladder disease because they live their lives in a state of chronic dehydration.
Cats are also picky water drinkers. Have you ever know a cat that will only drink out of a running faucet or a glass of water? These cats are often the ones that do not take in enough water to stay healthy.
So now, what do you feed your cat?
Learn to read pet food labels so you are familiar with what you are feeding your cat. A fresh(ideally raw), balanced commercial diet is the simplest way to feed your cat. See my post on reading ingredients.
You will likely need to experiment and find the texture and type of meat that your cat likes best, and it is a good idea to change the food around a bit. Many cats will stop eating a certain food if it is fed for long enough. Remember also that there is no guarantee that the pet food will remain the same – ingredients and processing methods typically change over time, and this may be the reason that your cat loses interest in a certain diet.