Cat Food Labels
Cats are true carnivores, requiring a meat-based diet for optimal health. Their natural diet is prey such as rodents, lizards, insects, and birds. These prey consist primarily of water, protein and fat, with less than 10% carbohydrate (starch, sugar and fiber) content. Cats are exquisitely adapted to utilize fat and protein for energy. They are not at all like dogs and people, who are adapted to use carbohydrates for energy.
When feeding our companion cats, the most logical strategy is to feed the diet that most closely mimics the natural prey diet. A homemade diet is a good way to accomplish this. Feeding more (or only) canned food is another way. Canned foods are higher in fat and protein, and lower in carbohydrates, than dry foods. Their high water content increases the cat's overall fluid intake, which keeps the kidneys and bladder healthy. The higher fat contributes to skin and coat health. Because the ingredients are more easily digested and utilized by the cat's body, canned foods produce less solid waste in the litterbox.
Another feature of the cat's natural diet is variety. A hunting cat doesn't one day decide to eat only purple finches! He will eat any small prey he can catch: chickadees, mice, grasshoppers, robins, or rabbits. Likewise, we should feed our cats a variety of foods. Variety keeps cats from becoming finicky and food-addicted, lessens the chance of dietary excess or deficiency of any single nutrient, and may prevent the development of food intolerances, allergies, and inflammatory bowel disease.
Dry food contains 35-50% carbohydrates, mostly as starch. This is necessary because the equipment that makes dry food requires a high-starch, low-fat dough for proper processing. Cereal grains provide an inexpensive and plentiful source of calories, which allows manufacturers to produce foods containing adequate calories at an affordable price. A few dry foods provide less carbohydrates, in some cases substituting starchy vegetables and soy for cereal grains; but they are still heavily processed and just as dehydrating (if not more so) than regular dry food.
Adult cats need 2-3 times more protein than dogs. Yet dry cat foods generally supply only about 1/3 more protein than dry dog foods-about 30-35% in dry cat food compared to 20-26% for the average dry dog food. "Kidney" diets for cats in renal failure are even more restrictive with 26-28% protein (such diets should never be fed to normal cats as they will cause muscle wasting as the cat breaks down its own body for protein). Canned cat foods contain 45-50% protein, and canned kitten foods may contain up to 55% protein. (All percentages calculated on a dry matter basis.)
Cats are attracted to food that has a strong meat or fat flavor. Pet food manufacturers go to great lengths to make their starch-based dry foods palatable to cats. They may coat the kibbles with fat or with "animal digest," a powder made of chemically or enzymatically digested animal by-products. The result may be a cat who overeats, not because he's hungry, but because he loves the taste of the food and doesn't want to stop.
Dry food is very dehydrating. Our feline friends descend from desert-dwelling wild cats who are well adapted to limited water resources. Their ultra-efficient kidneys are able to extract most of their moisture needs from their prey. However, the end result is that cats have a very low thirst drive, and will not drink water until they are 3-5% dehydrated (a level at which, clinically, a veterinarian would administer fluid therapy). Cats eating dry food take in only half the moisture of a cat eating only canned food. This chronic dehydration may be a factor in kidney disease, and is known to be a major contributor to bladder disease (crystals, stones, FUS, FLUTD, cystitis).
Caution: adding water or milk to dry food does not solve the problem; and the fact that there are always bacteria on the surface of dry food means that adding moisture can result in massive bacterial growth--and a very upset tummy.
The high heat used in processing dry food damages (denatures) the proteins in the food. The resulting unnatural proteins may trigger an immune response that can lead to food allergies and inflammatory bowel disease.
There is increasing evidence that carbohydrates (starches and sugars) in dry food are simply not metabolized well by many cats. While obesity is caused by many factors, the free-choice feeding of highly palatable dry food to a relatively inactive cat is a major player. Obese cats are prone to joint problems, liver and kidney disease, and diabetes.
Recent research has shown that high-carbohydrate diets are to blame in most cases of feline diabetes.
Many overweight cats are carbohydrate-intolerant, and should be fed low-carbohydrate diets. This means canned food. Experts are now recommending canned kitten food as the primary treatment for diabetes; many diabetic cats in a recent study decreased or even eliminated their need for insulin, simply by changing to a high-protein, low-carbohydrate diet. Ultimately, canned food may be even more beneficial as a preventative for this devastating disease.
Overweight cats may greatly benefit from a switch to an all-canned diet. Stick to foods containing 8% or less carbohydrate. Many all life stages and kitten foods fit this requirement. Carbs are usually not listed on the label. However, all you have to do is subtract the other ingredients from 100% to get an estimate of the carb content. Most cats lose weight more efficiently on a canned food than dry food diet. Even though they're often eating more calories, these diets are much better suited to the unique feline metabolism.
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 an hour each, morning and night. 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.
Quality is just as important with canned cat food as any other type of food. If possible, buy the food in a larger can, and store leftovers in a glass jar in the refrigerator. Pop-top cans, by-products, and fish flavors of canned cat food have been linked to the development of thyroid disease in cats.
Dry food is a great convenience and may be necessary in some cases when the guardian is gone long hours or cannot feed on a regular schedule. But at least 50% of the diet (preferably 100% if you want to ensure optimum health!) should be a high-protein, high-moisture, low-carb diet such as canned or homemade food.
Your cat will be healthier, and while you'll spend a little more on food up front, ultimately you'll save hundreds, if not thousands, on veterinary bills!
Pet food regulations do not allow the word carbohydrate on the label. Human foods are required to list carbohydrates on the label, however. This major difference makes it difficult to evaluate foods for cats. That's why concerned shoppers must do the calculations for themselves.
Fortunately, pet food labels provide the information you need to do them. To evaluate the analysis panel of dry, canned and frozen foods, we suggest using the simple formulas that follow.
The biggest building blocks of cat foods (the macronutrient content) are protein, fat, moisture and carbohydrate. Their total must equal 100 percent. How to calculate carbohydrates: Subtract the weight of crude protein, total fat, moisture and ash from the total weight ("wet weight") of the sample of food.
The Ash Content
Ash is sometimes listed, usually for cat foods (some conventional veterinarians believe ash is a factor in urinary tract disease). Ash is what remains after the food is burned. It consists primarily of elements, including calcium, phosphorous, iron, zinc and selenium. Typically, ash content is in the 5 percent to 8 percent range, on a dry-matter basis.
A Guaranteed Analysis of pet food is required information on the labels of treats and foods. Here's an example of the typical adult dry food:
Minimum percentage of crude protein: 26 percent
Minimum percentage of crude fat: 15 percent
Maximum percentage of crude fiber: 4 percent
Maximum percentage of moisture: 10 percent
These numbers tell you the percentages by weight of the macronutrients. In 100 grams of this food, there are 26 grams of protein (minimum), 15 grams of fat (minimum), 4 grams of fiber (maximum), and 10 grams of moisture (maximum). Because fiber is considered a carbohydrate, don't subtract the fiber when you do your calculating.
The label of a typical wet food states:
Minimum protein: 10 percent
Minimum fat: 8 percent
Maximum moisture: 75 percent
Maximum fiber: 3 percent
To compare dry and wet foods, you must remove the water from the food. What remains is the dry matter (DM): Protein, fat, carbohydrate and ash. A dry matter analysis tells us the percentage of DM that is protein, fat and carbohydrate. With these results, now it's possible to compare the macronutrient content of dry and canned foods.
Compare these foods on a dry matter basis.
A better picture of the overall balance of the diet emerges when the actual percentage of calories from each nutrient is known. Fat provides 8-9 kcal per gram, more than twice as much as carbohydrates and protein, which provide 3.5-4 kcal/gram, depending on the quality of the food.
Compare the percentage of energy provided by protein, fat and carbohydrate for five different foods: Typical dry food, canned, frozen, natural diet and senior dry food.
Here trere are the striking difference between the profile of the natural diet and dry or senior foods. Premium canned and frozen foods provide a more natural macronutrient content, with fat providing about 50 percent of the calories.
Choosing foods becomes much easier when you know what the balance of the animal's natural diet really is! We think almost all cats will feel much better eating diets very close to that natural balance.