By Dr. Becker
Five years ago, I published a list of 13 types of pet foods ranked from best to worst. That video remains one of the most popular here at Mercola Healthy Pets as well as on YouTube. There have been a few updates since I made that video, so I thought it was time to publish a new revised list.
When Deciding What to Feed Your Pet, Remember: Your Dog or Cat Is a Carnivore
First and foremost, when you're deciding what to feed your dog or cat, it's important to remember that your pet is a carnivore. His genetic makeup and internal workings remain essentially the same as his wild carnivorous ancestors.
Your dog or cat can't move his jaws from side-to-side, only up and down. That's because carnivores grab their prey, tear it into chunks with their sharp, interlocking teeth, and gulp it down without chewing.
Omnivorous mammals (for example, humans) have sharp teeth plus wide flat molars designed for chewing. Vegetarian animals have mouths full of wide, flat molars designed for excessive mastication (a lot of chewing). In fact ruminants, for example, cows, actually chew their food twice.
All carnivores, including dogs and cats, have very short digestive tracts compared to vegetarian animals. This is because nature designed carnivores to be able to eat foods that are heavily contaminated with pathogens. Wild dogs and cats don't remove the colon or other bacteria-laden body parts from prey animals before they eat them.
So, their digestive tracts are designed to get food in and out very quickly to limit exposure to pathogens. A carnivore's digestive system isn't designed to ferment foods like the GI tracts of vegetarian animals.
Your Pet's Ancestral Diet
The ancestral diet of a carnivore includes lots of variety and seasonal variability because certain prey is more available at certain times of the year. Wild dogs and cats thrive by consuming fresh, living whole foods. The food is moisture-dense because prey animals are about 70 percent water, plus it's high in protein and minerals, and moderate in fat.
There are no obese rabbits or other small prey animals in the wild, which is why dogs and cats do best with a diet containing moderate to low amounts of high quality animal fat and a very low percentage of carbohydrates.
The only carbs wild cats consume are what is naturally found in the gastrointestinal tracts of their prey, plus the occasional nibble of grass which provides added fiber and enzymes.
Wild dogs (including wolves) are scavenging carnivores, so their diets are more varied than wild cats. Like cats, they catch, kill, and consume whole prey, but they also eat carrion (dead animals). You'll never see a cat going anywhere near a dead animal as a food source.
Wild dogs also eat poop, grass, berries, and other plant matter. In fact, research shows that up to 30 percent of the stomach contents of wolves contain plant matter.
Processed Pet Foods Have Created Generations of Nutritionally Deficient Dogs and Cats
Commercial pet food is a relatively recent development, having been around only about 100 years. During that time, major pet food companies have produced most of their products using a base of corn, wheat, or rice.
However, they are now recognizing that feeding carnivores an abundance of grains causes cancer and creates fat, diabetic animals, so the industry is turning to grain-free dry foods. This move has re-ignited the popularity of kibble, but the problem is that biologically inappropriate levels of high-glycemic starches like potatoes and pea flour have taken the place of grains in dry pet food.
Another recent development is the use of trendy sources of carbs in pet food, for example, lentils and garbanzo beans. However, in addition to increasing the carb content beyond what is species-appropriate, legumes contain lectins, which are molecules that can create GI inflammation and irritation.
Fortunately for pet owners, dogs and cats are among the most resilient animals on the planet. They're able to survive when fed foods they were never designed to eat.
However, degeneration does occur in these animals as a result of inappropriate nutrition. But because the changes are gradual and often hidden until a disease is full-blown, we've been able to deceive ourselves into believing that convenience pet foods are actually good for dogs and cats. But in my opinion, we've created dozens of generations of nutritionally compromised animals that suffer from degenerative diseases linked to nutritional deficiencies.
Processed Diets Can Also Contain Carcinogens
Not only are processed pet foods biologically inappropriate, they also contain added synthetic vitamins and minerals to meet basic nutritional requirements. The food is heated to very high temperatures, which at best denatures proteins and decreases nutrient value. At worst, it introduces carcinogens into your pet's body on a daily basis.
Two potent cancer-causing substances are created when dry pet food is made by the extrusion process. When protein is extruded, carcinogenic heterocyclic amines are created. The byproducts of extruded starches are acrylamides. Both are known to cause cancer in dogs and cats. This is quite disturbing when you consider the fact that most pets across the globe are eating dry food their entire lives, and the cancer rate is skyrocketing in companion animals.
Feeding dogs and cats inappropriate ingredients for several generations has created significant metabolic and physiologic stress. Convenience pet foods are the root cause of the inflammatory processes and degenerative diseases that plague today's dogs and cats. A biologically correct diet for a carnivore is high in moisture, high in protein, moderate in fat, and low in carbohydrates. The vast majority of pet foods on the market today are the opposite – low in moisture content, with low to moderate amounts of poor quality protein and fat, and high in starches or carbs.
Feed Your Pet the Best Diet You Can Reasonably Afford
The goal in feeding your pet a diet she can truly thrive on is to mimic the ancestral diet of dogs and cats as closely as possible without breaking the bank.
Now, I know some of you might be thinking "Gee, I would like to feed myself an all-organic, free range, non-genetically modified, and fresh food diet… but I just can't afford to." I certainly understand, and my basic recommendation is to feed yourself and your pet as much unprocessed, fresh food as you can afford.
I have clients who can't afford to feed an all-fresh, living, and raw food diet, so they offer fresh food snacks instead. Research shows that offering some healthy foods is better than offering no healthy food at all.
I also have clients who can afford to feed their pet maybe 2 to 4 fresh food meals out of 14 in a week. Others do a 50/50 split, meaning one meal a day is a processed pet food, and the other is a fresh food meal.
I recommend taking baby steps toward providing the best diet you can afford for your dog or cat.
Updated List of Best-to-Worst Types of Pet Food
1. Nutritionally balanced raw homemade diet. This is the best diet you can feed your dog or cat. It's very important not to wing it when preparing your pet's meals at home. I say this because when pet food nutrition expert Steve Brown and I analyzed many of the homemade and prey model diets available, we learned they fall far short in trace minerals, antioxidants including nutrients like manganese, magnesium, vitamin E and D, copper, zinc, iron, choline, and essential fatty acids.
Additionally, if the diet doesn't have a proper fat or calcium to phosphorus balance, it can actually cause a myriad of health problems, especially in growing animals. So, it's critically important that you know your homemade diet is balanced.
The great thing about homemade raw diets is you get to handpick the ingredients. You know the quality of the meat you're using. And if your dog is allergic to chicken, for example, you simply pick a different protein source. Another benefit is you can wash the veggies to your own satisfaction to remove any pesticide residue.
Making your own pet food can provide peace of mind because it's becoming increasingly more difficult to find ethical pet food companies that use locally sourced or even US-grown ingredients. With homemade food, you're in complete control of every ingredient that enters your pet's body.
And of course, raw food is just that. It's raw and unadulterated. It contains all of the enzymes and phytonutrients that are typically destroyed during food processing.
Homemade food also gives you the flexibility to include a lot of nutritional variety in your pet's diet. You can buy seasonal fruits and veggies on sale. You can use produce that comes from your local supermarket, your local farmer's market, or even from your own garden.
2. Nutritionally balanced cooked homemade diet. This option gives you all of the benefits of the homemade raw diet above, minus the benefits of the free enzymes and phytonutrients found in living foods. Interestingly, there are a few nutrients that are actually more bioavailable when cooked, for example, lycopene.
Reasons to cook your pet's meals include the fact that some animals prefer cooked over raw food, or warm food over chilled food. Also, some pet owners simply prefer to cook the food. And then, there are some medical conditions such as recent GI surgery or pancreatitis for which cooked food is just a better idea.
3. Commercially available balanced raw food diet. Again, it's critically important that the diet be balanced. There are a lot of raw diets on the market these days that are nutritionally incomplete. These foods should say right on the label, "For supplemental or intermittent feeding." I don't recommend feeding unbalanced foods without adding in the missing nutrients, or your pet can have nutrition-related medical problems in the future.
Commercially available balanced raw food diets are found in the freezer section of small or privately owned pet boutiques. Some big-box stores are now starting to carry a larger selection of frozen raw diets, and you can also find an excellent selection online.
There are new raw diets coming on the market every month and vegetable, bone, and fat content vary widely between products. For example, diets range from 0 to 40 percent in vegetable content. This can impact the amount of synthetic vitamins and minerals that must be added to the diet to make it nutritionally complete. In addition, vegetable content impacts digestive and stool health. So if, for example, you have a dog who suffers from chronic constipation, you may want to choose a food with higher veggie content.
Commercially available raw food diets also range from low fat to high fat. If you have an obese cat, you would want to select a low-fat diet, but if you have a highly active dog on the lean side who loses weight quickly, it would make sense to choose a higher fat food.
Ground bone, bone meal, or a bone meal equivalent is typically added to raw diets for mineral balance. Some raw foods contain bone pieces that are actually too big to be safely cooked, so if you choose a raw diet and want to cook it, make sure it's safe to do so.
When it comes to ingredient sourcing, some raw food companies pride themselves on using only healthy, grass-fed animals and organic veggies. Others use animal meats and produce imported from China or other countries, as well as factory-farmed and GMO-fed animals raised in feedlots here in the US.
Some use whole foods to meet trace mineral requirements, while others use very few ingredients and rely on vitamin and mineral pre-mixes to meet their nutritional requirements.
Another factor to consider is how the raw food is formulated. Meat-based foods like raw diets are almost always calorically dense. They should be formulated on a caloric basis and not on a dry matter basis. This is a more demanding method of formulating. Comparing the formulation on a dry matter basis to caloric basis shows that raw foods formulated on a dry matter basis actually fall significantly short of nutrients.
You know a raw diet is formulated on a caloric basis when the nutrients are listed as a gram or milligram of nutrient per 1,000 kilocalories. Diets formulated on a dry matter basis will have nutrients listed as a percentage of dry matter. I only recommend choosing raw foods that are formulated on a caloric basis.
How companies manage potentially pathogenic bacteria is another consideration, and ranges from manufacturers who do nothing, to those who batch test, use UV treatments, ozone, fermentation, or HPP (high pressure pasteurization).
Fortunately, this sector of the pet food industry is the fastest growing category, which means you should be able to find a food that fits your ethical and financial parameters, with the added convenience of not having to make the food yourself. The downside is the cost – you're paying for the luxury of having someone else do the work for you. As with all pet food manufacturers, you'll need to investigate the company you're buying from to make sure you're feeding the correct product for your pet's specific nutritional and medical goals.
4. Dehydrated or freeze-dried raw diet. If you can't or don't want to feed fresh raw food, a good alternative is a dehydrated freeze-dried raw diet that is reconstituted with water. These diets are shelf-stable so they're very convenient. To make them biologically appropriate, all you have to do is add water.
Dehydrated or freeze-dried raw diets haven't been processed at high temperatures. In many cases, the nutrient value has been retained minus a balanced fatty acid profile.
Keep in mind that there is a difference between fresh and dehydrated or freeze-dried raw food. Dehydrated and freeze-dried foods by definition are not the same as fresh raw diets, but they can be a great choice for people on the move, people who go camping with their dog or cat, and for pets that go to day care or need to be boarded. It's really the next best thing to a fresh raw food diet. Make sure the brand you select is nutritionally balanced for all life stages.
5. Commercially available cooked or refrigerated food. This is a new category of pet food that is exploding in the marketplace. These diets have been gently heat-processed so the proteins are slightly denatured, but the moisture content is excellent. The food is fresher than processed diets, so the nutrient content is better than choices lower on this list. You'll find these foods in the refrigerated section of pet stores, and in many human grocery stores as well.
The quality of raw materials in refrigerated pet food ranges from absolutely terrible to excellent, so you do need to do some research before choosing which brand to buy.
6. Human-grade canned food. If the package label or the manufacturer's website doesn't say the ingredients are human grade, you should assume they are not. Pet food made with human grade ingredients is a great deal more expensive than feed-grade or animal-grade canned food. These foods will typically be found in boutiques and small independent retailers that focus on high-quality foods.
7. Super premium canned food. These products are typically found at big-box stores like Petco and PetSmart, or a conventional veterinary clinic. These diets contain feed-grade ingredients (which mean foods not approved for human consumption). But, the moisture content is much more biologically correct than dry food. Many have excellent protein, fat, fiber, and carb ratios.
8. Human-grade dry food. Dry food is not biologically appropriate for dogs or cats in terms of moisture content when compared to the ancestral diet. Additionally, even grain-free dry foods contain unnecessary starch that can cause inflammation issues in your pet.
Human-grade is very important because the ingredients have passed quality inspection, which means they don't contain poor quality or rendered unidentified proteins. If the food has been baked, it will clearly say so on the label. Otherwise, you should assume it has been extruded, which means you are probably feeding a small amount of carcinogens to your pet with every meal.
9. Super premium dry food. These diets are found at big-box stores and conventional veterinary clinics. These extruded dry foods are made with feed-grade ingredients not approved for human consumption but are typically naturally preserved. Most of these foods contain added grains or starches, which are not species-appropriate and may harbor mycotoxins.
10. Grocery store brand canned food. These foods rank below super premium dry foods because even though the moisture content is more biologically appropriate, they usually contain high levels of unnecessary grains and synthetic toxic preservatives such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), and ethoxyquin.
11. Grocery store brand dry food. These diets have all the same issues as grocery store brand canned food, and also do not contain adequate moisture.
12. Semi-moist pouched food. This stuff is really bad. The reason it is so far down the list is because in order to make the food semi-moist, the manufacturers must add an ingredient called propylene glycol. Propylene glycol is an undesirable preservative that is closely related to ethylene glycol, which is antifreeze. While propylene glycol is approved for use in pet foods, it's unhealthy for dogs and cats to consume.
13. Unbalanced homemade diet, raw or cooked. Dead last on the list for good reason is an unbalanced homemade diet. Some pet owners believe they can offer their dog or cat a chicken breast and some veggies, and call it a day. Many caring pet owners are unfortunately sorely lacking in knowledge about their companion animal's nutritional requirements.
Feeding fresh homemade food is a good thing, however, if the diet you're offering your pet is nutritionally unbalanced, it can cause significant irreversible and even potentially fatal health problems. These include endocrine abnormalities, skeletal issues, and organ degeneration as a result of deficiencies in calcium, trace minerals, and essential fatty acids.
Almost every veterinarian has seen seen patients that have been harmed by well-meaning owners who feed unbalanced diets. It's heartbreaking and entirely preventable. Homemade pet diets must be done right or not at all.
Where Does YOUR Pet's Diet Fall on the List?
If the diet you're feeding your dog or cat falls into one of the lower quality categories, don't panic. Most people are feeding their pets lesser quality foods because they either can't afford to feed a better food, or they simply don't know what constitutes good nutrition for their pet.
If your pet is eating from the lower half of the list, set a goal to feed better quality foods now that you know can make a difference, or as soon as you can afford to feed a more nutritious diet.