Based closely on an article written by Jean Hofve, DVM.
Unlike dogs, cats are obligate (strict) carnivores, requiring a meat-based, moisture rich diet for optimal health, they cannot easily digest plant proteins and carbohydrate laden dry foods.
1. Cats lack the metabolic pathway that humans and dogs use for processing carbohydrates and plant proteins. Cats are exquisitely adapted to utilize meat protein and fat for energy. While cats can digest and utilize a small amount of carbs, the excess gets turned into body fat. This is why over half of all US cats are overweight and the vast majority of these cats are fed dry food. Take it one step further and consider the rising rate of feline diabetes, most often seen in overweight cats. Diabetes is now considered by experts to be caused by dry food, and it’s clear that we need to take a different approach to feline nutrition!
Dry foods typically contain 30-40% carbohydrates or more. Even the “Grain-free” dry cat foods most often contain just as many carbohydrates in the form of starchy vegetables and beans. Cereal grains, lentils and vegetable starches provide an inexpensive and plentiful source of protein calories, which allows manufacturers to produce UNHEALTHY cat foods containing adequate percentages of protein calories at an affordable price.
2. Cats have a very low thirst drive and will not drink water until they are up to 3% dehydrated. This is a level at which, clinically, a veterinarian would administer intravenous fluid therapy. Cats eating only dry food take in just half the moisture of a cat eating only canned food. This chronic dehydration may be a factor in kidney disease, and is a major contributor to bladder disease (crystals, stones, FUS, FLUTD, cystitis).
A prominent feature of the cat’s natural diet is a high water content - they should get most of their moisture through their diet, not a water bowl. Dry diets containing 10% water are completely unnatural and unhealhty for cats.
Caution: Adding water to dry food does not solve the problem; there are always bacteria on the surface of dry food which means that adding moisture can result in massive bacterial growth – and a very upset tummy.
3. Adult cats need 2-3 times more protein than dogs, yet dry cat foods generally supply only about 30-35% protein and a whopping 30-40% or more carbohydrates. Canned foods are almost always higher in protein and much lower in carbohydrates than dry foods. Their high water content increases the cat’s overall fluid intake, which keeps the kidneys and bladder healthy. Canned food ingredients are more easily digested and utilized by the cat’s body, and therefore typically produce less solid waste in the litterbox.
The average canned cat food contains about 45% protein and 8-10% carbohydrates. This is much closer to the cat’s preferred diet of 52% protein, 36% to 46% fat, and 2% to 10% carbohydrates.
4. The high heat used in processing dry food denatures (damages and distorts) the proteins in the food. The resulting unnatural forms may trigger an immune response that can lead to food allergies and inflammatory bowel disease. If that's not bad enough, remember that the carbohydrates (starches and sugars) in dry cat food are not metabolized well by cats, and it becomes clear why our felines are developing a number of serious health issues by middle age, if not sooner.
Feline nutrition experts are now recommending a high animal protein canned food as the primary treatment for diabetes. Many diabetic cats can decrease or even eliminate their need for insulin simply by changing to a high-animal-protein, low-carbohydrate diet. Ultimately, canned food may be even more beneficial as a preventative for this devastating disease.
5. Cats lose weight far more efficiently on a canned food than dry food diet; they lose body fat while retaining muscle mass. These diets are much better suited to the unique feline metabolism.
Transitioning to Canned
If your cat is not used to eating canned food, add it to the diet slowly in small amounts. It is so different in composition from dry food that it may cause tummy upset at first. If a cat won’t eat canned food, it’s usually because of a dry food addiction, or because he isn’t hungry enough to try something new. Start by putting the cat on a meal-feeding schedule, leaving dry food out only a half hour at a time, 2-3 times a day. Once he’s accustomed to the schedule, put a little canned food down first. Most cats will be willing to try it at that point
Dry food is a great convenience, but a cat’s diet should be high in animal-protein, high in moisture, and low in carbohydrates - such as canned or a specially prepared raw food.
Your cat will be much healthier, and ultimately you’ll save hundreds, if not thousands, on veterinary bills!