Since a cat metabolizes primarily fat and protein for energy, most of the carbohydrates in the diet are then stored as body fat. Both products are overprocessed and based on refined carbohydrates. Added vitamins attempt to compensate for nutrient loss, but the food still lacks many other essentials including enzymes, complete amino acids and fatty acids. Neither reflect the natural diet or nutritional needs of either species. However, in the opinion of the individual consuming it, both taste good .
Water is the most important nutrient.
Of course, neither we nor our cats can live on water alone, but its importance is demonstrated by the fact that during the absence of food and water a creature will perish from thirst long before perishing from starvation. That said, we don't claim that cats die of dehydration when fed on a commercial dry cat food diet, because most cats will have a supplementary source of water available of which they will take advantage. We mentioned previously how cats evolved as dwellers of the African plains and desserts, and their adaptation of stilling their needs for water with the moisture content of their prey. During the past 40 million years, the cat did not need to rely on supplementary water intake and, even if needed, the cat would not readily do so, because to her it is not natural. A cat fed a commercial dry food diet will consume approximately one cup of the product per day.