Pet Nutrition, Basic Concepts and Common Misconceptions.
By Dr. Duane Dust
Most of my clients are aware of my keen interest in pet nutrition. All have heard my evaluation of their pet's body condition, even if that has not been an enjoyable conversation. If you are unlucky, you have had to put up with one of my harangues concerning pet foods, such as the lack of useful nutritional information on the bags and cans, unrealistic feeding recommendations, etc. Since it is my belief that the best medicine is good nutrition (and regular exercise), I will now touch briefly on the subject of nutrition of dogs and cats.
Foods and feeding strategies.
The first and foremost issue is the problem of overfeeding. About one half of all adult dogs and cats are overweight. Obesity is a direct cause of many common medical problems such as chronic arthritis (very common), diabetes, liver disease, pancreatitis and much more. Statistically, obese pets die years earlier than dogs and cats of normal body condition. These problems cause a lot of suffering, as well as premature death. Pets love to eat of course, just like us, but few people understand how much food their pet should be eating and even fewer have a good idea how many calories they are actually feeding. So here is a bit of information on how to determine how much your pet should eat and how to tell if you are feeding too much. For reference, a cup is an 8 oz. measuring cup. Keep one in the bag and measure each meal.
Keep in mind your pet's nutritional needs. Kittens and puppies require double the calories of adult dogs and cats. Neutering lowers caloric needs by about 20% and obese prone animals need to have their intake lowered by another 20%. Exercise increases calorie needs but unless your dog is running every day don't feed more. Cats do not exercise. How do you know if your pet is overweight? If you cannot easily feel ribs or if you don't see a nice hollow between the last ribs and the hind legs, your pet is overweight.
The average neutered adult, 10lb. cat needs in the vicinity of 200-250 calories per day. I feed my cats about 180 calories per day. Dogs of course vary greatly in size and the larger they are, the less calories per pound they require. A 20lb. adult neutered dog needs about 500 calories/day, a 40lb. dog needs 900 calories/day, and an 80lb. dog needs 1500 calories/day. Some dogs need more than this, but I feed my dogs less. Yes, they seem hungry all the time but If I fed them twice as much they would still act hungry all the time. A good starting point is to feed about 2/3 of the amount recommended on the bag. Practice portion control!
Read the label.
It is truly pathetic how little nutritional information and how much misleading promotional garbage is on the average pet food container. Calorie content per cup or can is not required by law and is often not present. Protein, fat, fiber and moisture content is required, but only as maximum or minimum levels, not the actual amounts. An ingredient statement is required which lists the ingredients in decreasing order, but this is widely manipulated to make it appear that the "good" ingredients appear first. There is no information on the actual amounts of any ingredient.
There are two methods for determining the nutritional adequacy of pet foods. The gold standard is the "Feeding trial method" in which the food must undergo lengthy feeding trials to determine its nutritional soundness. This is obviously an expensive and time consuming process. Hill's (Science Diet) is the best known example of a pet food company that uses feeding trials for their foods. The other method is the "Formulation method" in which the food is formulated to meet accepted nutritional standards. With this method, digestibility and palatability of the ingredients is not known. The vast majority of pet food manufacturers use this method. These pet foods are marketed without ever having been fed to a single animal. This worries me a bit. Food packages are required to state which method is used for that, but often you have to study the bag to find it.
How do you find out how calorie rich your pet food is? You may not be able to find out. As a general rule of thumb, most dog foods are between 350-400 calorie/cup without much variation between puppy, adult and senior foods. Some brands are considerably higher in calories. Blue Buffalo foods can run over 500 calories/cup and Canidae All Life Stages is close to it. No wonder so many dogs are overweight. "Light" foods are required to be much less rich, usually under 300 calories/cup and therefore are usually a better choice for most mature dogs. Canned foods are hard to categorize because there a big differences in water content and also some can to can variation although most 13 oz. cans run 350-500 calories.
Cat foods are even more variable than dog foods. Dry foods typically run 450-500 calories/cup with senior foods usually not significantly less. "Light" foods are much lower in calories, around 300 calories/cup. Most adult cats are better off eating a fight food. Canned foods average 75-100 calories/ 3 oz. can and 150-200 calories/ 5 1/2 oz. can.
Canned vs. Dry.
There is a bit of controversy concerning feeding cats. Some people feel that dry food, due to higher carbohydrate content, leads to sugar diabetes in cats. More on this in a bit. Dry food is more economical, less prone to spoilage, less apt to result in dental disease and more consistent nutritionally. I feed my cats mostly dry food but offer canned food once or twice a week as a change of pace. My dogs eat dry food almost exclusively. The all eat Hill's Oral Care. I like clean, healthy teeth and the lower calorie content.
Pet Food Industry Myths.
Fads and misinformation thrive in the pet food business and new and different is often not better. I would like to shed some light on some of these.
Grains are bad and cause diabetes - Grains are carbohydrate (starch) sources and are a good, highly digestible source of energy. Diabetes is a disease of obesity, not of grain consumption. Grains are not a "'natural" food for carnivores, but no commercial grain free food is remotely similar to what is natural for wild canines and felines. One can make a case for lowering carbohydrate consumption in both pets and humans, but that discussion is well beyond the scope of this blog. The current generation of grain free dog and cat foods tend to be very rich and very prone to causing obesity.
Corn is not digestible and causes allergies - This myth drives me nuts because it is so completely off base. Corn has the highest digestibility of all commonly fed carbohydrate sources, such as rice, barley, etc. It is also higher in protein, antioxidants, fatty acids and beta carotene as well. Corn almost never causes allergies. Food allergies are caused almost exclusively by protein sources, just as in people. Case closed.
Fiber is bad - I have seen fiber referred to as filler, junk, floor sweepings, etc. A discussion of the types and benefits of fiber is not appropriate here because it is an incredibly boring topic, so I will be brief. Fiber is good. Fiber decreases calorie content, improves constipation, firms up chronically loose stools, prevents anal sac impactions and infections and is generally good for colon health. A dog or cat is not happy if their bowels are not happy.
Byproducts are bad - Byproducts are defined as foods produced in the process of making something else. Vitamin E, vegetable oils and organ meats are all byproducts. We all would be better off if we ate more byproducts.
Raw diets are superior to commercial foods - These foods usually contain a mix of raw meat, bones and vegetables. Raw diets can be beneficial for some dogs with food allergies because of their limited number of ingredients, and hence less potential allergens. There are some distinct disadvantages, however. There is no evidence of overall nutritional superiority. Some recipes in fact have excesses or deficiencies of some nutrients, particularly calcium and phosphorus. There is a very high incidence of E Coli and Salmonella contamination. Owners are exposed to these infections by handling the food or physical contact with the pet. Raw diets are not recommended for service dogs or dogs that come in contact with children, immune suppressed individuals or the elderly. Foods are cooked for good reasons. There is also a demonstrated increased incidence of broken teeth, intestinal obstruction and gastrointestinal perforation. Some dogs do well on raw diets, but this is a buyer beware situation.
Organic foods are better nutrition - Organic foods are identical to non organic foods in all respects. The reason we all should consider purchasing organic (USDA Certified) is that these foods promote sustainable, pesticide free agriculture for both plant and animal foods. By the way, the terms "holistic" and "natural" have no nutritional meaning whatsoever. Manufacturers slap these terms on their bags for marketing reasons only.
Homemade foods - This topic deserves an entire chapter in a nutrition textbook, so I'm not touching it. Suffice it to say that most people do it way wrong. Do your homework if you are going to try this.
I have likely strained the patience of everyone who has chosen to read this article, so I will now wrap it up. We all like to feed our pets. It makes them happy and it makes us happy, but the old adage of moderation in all things applies doubly to the subject of mealtime. Moderation in feeding, along with some daily exercise makes for a healthy happy pet. Keep your vet bills low and measure out that food!