Written by Lisa A. Pierson, DVM
This is where it gets tough. The current labelling system for pet foods is seriously lacking in usable information. The "guaranteed analysis" numbers that you find on a can of food simply gives a wide range of the levels of water, protein, fat, etc. that are contained in the food. You can get a rough idea of what is in the food but, ideally, it should be mandatory to put the more accurate "as fed" values on the can. However, I do not see this happening anytime soon. This would be more along the lines of the information that we find on our own packaged foods.
Looking at the list of ingredients also gives an incomplete picture of what is actually in the food in terms of amount of each ingredient. Without knowing the actual amount of each ingredient, we have no idea of the impact of the ingredient on the nutritional profile of the food. For instance, when we see a high carbohydrate ingredient like rice on the label, we know that this food item has no business being in cat food but how do we really know the quantity of rice that is in the food? Is it present in a small amount or a large amount? This is why it is important to not just consider the list of ingredients but to also look at the protein/fat/carbohydrate profile of the food which can be seen in a chart for many commercial foods.
A good example of the above issue is a food like canned Wellness®. At first glance, this food may be dismissed as inappropriate for a carnivore because it contains several high carbohydrate ingredients in the form of fruits and vegetables. However, in reality, the low carbohydrate level (3-5%) tells us that the amount of fruits and vegetables is very low.
If a food that you are feeding is not included on the above list, you can contact the company and ask for the breakdown of their foods in terms of the calories that come from protein, the calories that come from fat, and the calories that come from carbohydrates. Optimally, your cat's diet should not derive more than 10 per cent of its calories from carbohydrates.
The words "natural" or "premium" or "veterinarian recommended" are not necessarily indicative of high quality. Also, if you are thinking about feeding any "breed-specific" food, please don't fall for the utterly absurd claims that these companies make regarding these diets. A Siamese is no different from a Persian or a Maine Coon — or an "alley cat" — when considering optimal dietary composition.
Contrary to what is often believed, many, if not all, of the so-called "prescription diets" sold in veterinary hospitals are not formulated for optimal health of a carnivore. Many of these products contain corn, wheat, and soy which have no logical place in your cat's diet and these diets are often very high in carbohydrates. Many of them also contain by-products as the main - and often only - source of protein. Please note that not all by-products are inferior in quality.
It is also important to note that Hill's — the maker of Science Diet® — continues to use extremely questionable preservatives such as BHA, BHT and ethoxyquin in many of their products. Other companies have abandoned the practice of using these chemicals as preservatives — opting for more natural and safer methods. Unfortunately, many veterinarians are very poorly educated in the area of nutrition. Too often their recommendations are taken from the pet food industry which does not always have your cat's best interest in mind when formulating their products. In most instances, you will be paying far more money than you should be for the low quality ingredients that many of these prescription products contain.
Look for a muscle meat (preferably, not an organ meat like liver) as the first ingredient. A muscle meat will be listed as "chicken," or "turkey," etc., not "chicken by-products" or "chicken by-product meal," or "chicken broth" or "liver." "Chicken meal" is technically a muscle meat but the term "meal" denotes that it has been rendered (cooked for a long time at very high temperatures) and is lower quality than meat that has not been as heavily processed. A "meal" product is more commonly found in dry foods. By-products can include feet, intestines, feathers, egg shells, etc. and can be less nutritious than meat. By-products can also be very nutritious organ meat but the problem is that we never really know what the term "by-products" includes.
Grains should be absent but, unfortunately, grains are cheap so they are included in many commercial cat foods. Think "profit margin." Grain is cheaper than meat. If grains are present, they should be minimal in amount. This is where checking out the carbohydrate content comes into play. It is ideal to feed a grain-free diet. Corn, wheat and soy are thought to be common allergens (as is yeast) and the carbohydrate fraction of these grains will also cause a rapid rise in blood sugar in many cats. Soy contains phytoestrogens and also negatively influences the thyroid gland. Given how common hyperthyroidism is in the cat, soy has no business being in cat food. Unfortunately, soy is a common ingredient used by pet food manufacturers.
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