Cats Need Animal-Based Protein
Cats are obligate (strict) carnivores and are very different from dogs in their nutritional needs. What does it mean to be an ‘obligate carnivore'? It means that your cat was built by Mother Nature to get her nutritional needs met by the consumption of a large amount of animal-based proteins (meat) and derives much less nutritional support from plant-based proteins (grains). It means that cats lack specific metabolic (enzymatic) pathways and cannot utilize plant proteins as efficiently as animal proteins. It is very important to remember that not all proteins are created equal. The protein in dry food, which is heavily plant-based, is not equal in quality to the protein in canned food, which is meat-based. The protein in dry food is, therefore, less bioavailable to your cat.
Do not be confused by the listing of the protein percentages in dry food compared to canned food. At first glance, it might appear that the dry food has a higher amount of protein than the canned food—but this is not true on a dry matter basis which is the accurate way to compare the two foods. Most canned foods, when figured on a dry matter basis, have more protein than dry food. And remember, even if this were not the case, the percentage numbers do not tell the whole story. It is the protein's bioavailability that is critical.
Carbohydrates - we are feeding our cats to much
In their natural setting, cats—whose unique biology makes them true carnivores--would not consume the high level of carbohydrates (grains) that are in the dry foods that we routinely feed them. You would never see a wild cat chasing down a herd of biscuits running across the plains of Africa or dehydrating her mouse and topping it off with corn meal gluten souffle! In the wild, your cat would be eating a high protein, high-moisture content, meat-based diet, with a moderate level of fat and with only ~6-9% of her diet consisting of carbohydrates. The average dry food contains 35-50% carbohydrates. Some of the cheaper dry foods contain even higher levels. This is NOT the diet that Mother Nature intended for your cat to eat! A high quality canned food, on the other hand, contains ~3-6% carbohydrates. Cats have a physiological decrease in the ability to utilize carbohydrates due to the lack of specific enzymatic pathways that are present in other mammals, and the lack a salivary enzyme called amylase. Cats not only have no dietary need for carbohydrates, but too many carbohydrates can actually be detrimental to their health, as outlined below. With this in mind, it would be as illogical to feed a carnivore a steady diet of meat-flavored cereals as it would be to feed meat to a vegetarian like a horse or a cow, right? So why are we continuing to feed our carnivores like herbivores? Why are we feeding such a species-inappropriate diet? The answers are simple. Grains are cheap. Dry food is convenient. Affordability and convenience sells. But is a carbohydrate-laden, plant-based, water-depleted dry food the best diet for our cats? Absolutely not. They are designed to eat meat – not grains.
Cats Need Plenty of Water With Their Food
Another extremely important nutrient with respect to overall health is water. It is very important for a cat to ingest water with its food, as the cat does not have a very strong thirst drive. This is a critical point. This lack of a strong thirst drive leads to low-level, chronic dehydration when dry food makes up the bulk of their diet. Cats are designed to obtain most of their water with their diet since their normal prey contains ~70% water. Dry foods only contain , 10% water whereas canned foods contain, 78% water. Canned foods therefore more closely approximate the natural diet of the cat and are better suited to meet the cat's water needs. A cat consuming a predominantly dry-food diet does drink more water than a cat consuming a canned food diet, but in the end, when water from all sources is added together (what's in their diet plus what they drink), the cat on dry food consumes approximately HALF the amount of water compared with a cat eating canned foods. This is a crucial point when one considers how common kidney and bladder problems are in the cat.
Cats are very different from humans with
respect their susceptibility to ‘food poisoning'. Cats have a much shorter
transit time through their intestinal tract than humans do. (~12 hours for the
cat versus ~35-55 hours for the human.) This is a very important point because
the more time bacteria spend in the intestines, the more they multiply,
eventually leading to intestinal upset. Purchasing free-range, antibiotic- and
hormone-free whole meats from a reputable butcher such as Whole Foods Market and
adhering to safe meat handling practices are important steps to take when
preparing a raw food diet. Good choices include dark poultry meats (such as
thighs and drumsticks which are more nutritious than white meats if you choose
to not grind a whole carcass) or rabbit. (See Resource List for more information
on recipes for home-prepared diets.)