Learning about the nutritional needs of cats means to understand the dramatic distinction between their needs and our needs as humans. We have to come to terms with the fact that what is good for us is not necessarily good for cats. Their radical differences from us are simply the result of choosing a different evolutionary pathway and the adaptation into a different niche in the ecosystem. Fresh, raw fruit and vegetables just doesn't cut it for our feline friends, and the ingestion of such foods could in fact result in painful indigestion. Over many millions of years, the ancestors of the modern domestic cat have evolved to be carnivores, and are perfectly and totally adapted to a lifestyle of predation on herbivores and the consumption of their flesh for sustenance.
In fact, all feline species are so successful as predators, that in the course of their evolution, they never needed to develop the ability to metabolize and synthesize nutrients from plant matter - making them into obligate or true carnivores who can not survive without the ingestion of meat.
When we compare the physiology and behaviour of the domestic cat to her ancestor, most likely to be Felis Silvestris Libyca - the African Wildcat, only mere changes in appearance can be noted - the result of selective breeding by humans. Otherwise, 3000 years in our company has had little effect on the cat and, after only one generation, cats are capable of reverting to a completely wild state.
In more recent years however, the well being of Felis catus left much to be desired, and statistics indicate a dramatic decline in health and, our domestic cat could be on the road to extinction.

One of the most significant and primary changes in the domestic cat's existence has been the source of her nourishment. Both a move from the fields and woods of rural areas into the city, as well as a desire for convenience by the care giver, condemned the cat to dependency on pre-prepared foods as sustenance - products which in no respect compare to her natural diet.
Good nutrition is the foundation of good health, and good health provides for survival of the individual and therefore of the species. When providing for cats under human care, it is justified to observe and adapt the behaviours and dietary habits of wild-living relatives. Long term observations have proven that domestic cats thrive on a diet comparable to that of wild cats of similar size, which comes as no surprise considering they are anatomically identical (even producing fertile offspring when hybridized). The opinion that domestic animals adapt to a more human like diet through the process of domestication is false. Domestication will impact social behaviour patterns of animals, and influence appearance through selective breeding, but can not alter the nature of an animal.