Choosing the Right Pet Food Can Be Scary

Trying to filter through information on the internet is a daunting task, with one group of people advising you to feed raw, one group advising to feed grain-free, and each brand promoting the benefits of their particular food.

On top of that, there had been a lot of news regarding the pet food and pet treat industry in regards to chemical additives, mold and bacterial contamination, recalled foods, and jerky treats that could potentially cause organ damage or organ failure.

Upon heading to the store and picking up a bag of pet food, reading the nutritional label can be a bit like trying to do complex math equations in a foreign language. How do you tell if you're choosing a good diet, or if you're paying too much for a sub-par brand name? Which food is best?

The truth of the matter is that finding the "best" diet for your pet is often a matter of opinion. "Premium" grain-free brands may not be as balanced as some of the more common pet food brands, and making a raw diet at home (or purchasing a pre-made one) is only as good as the chosen added ingredients.

Luckily, The Association of American Feed Control Officials (AAFCO) organization provides published minimum standards for dog and cat food content. While not all brands choose to meet that standard, many brands do. Brands that fall within the guidelines of the AAFCO nutritional profile can claim they are AAFCO approved.

Now, not all animals are the same, and a pet's nutritional needs change through puppyhood, adulthood, pregnancy, lactation, and their seniors years. While the AAFCO guidelines set a baseline standard for pet food, these standards vary from pet to pet based on age and lifestyle. Before delving into what makes a food "bad" or "toxic", it is important to understand your pet's nutritional needs. So let's break all of this information down into something more easily digested.

Nutritional Labels

Pet Food Label

When looking at the back of a pet food package, you notice there are two different areas - guaranteed analysis, and ingredients.The guaranteed analysis is very similar to the nutritional label found on human food and lists the minimum amount of any given nutrient in the diet. In addition, AAFCO standards require that foods have a certain balance of protein, fat, fiber, and moisture; so you will find the percent of each of those as well.

The ingredients are the individual parts that make up the whole diet. This is where you find the meats, bone meal, grains, vegetables, additives, preservatives, vitamins additives, etc. The label lists them from largest to smallest volume, so the first listed ingredient will be the ingredient of largest quantity in the food. As both dogs and cats are carnivores, the best packaged foods will have a type of meat listed as the first ingredient.

Dog Food

Dogs are nutritionally similar to humans in that they have somewhat similar dietary requirements (with a few notable differences). Like us, dogs are omnivores that lean towards being carnivores. This means that they are unable to survive on a solely meat diet. That being said, protein is the most important part of a dog's food. chicken, egg, or beef-based diets are of far higher quality than diets that consist mainly of corn and corn meal. Note that dogs are lactose intolerant, so they do not absorb proteins from milk and cheese nearly as easily as we do.

Looking purely at the numbers, small dogs require somewhere between 180-400 calories a day, whereas larger dogs may need somewhere between 1,000-2,000 calories a day. At least 18% of those calories should come from a protein source for an adult dog. By AAFCO standards, this means that the guaranteed analysis of crude protein should be at least a minimum of 18%. For puppies and pregnant or lactating bitches, this minimum is 22.5%.

Fats are the next most important part of a dog's diet. Many of the healthy vitamins such as Vitamins A, D, and E come from fatty acids. Ideally, a dog should get 9-15% of its calories from a source of fat in its food. AAFCO standards have set this minimum at 5.5% for adult dogs, and 8.5% for puppies and pregnant or lactating bitches. As you can see, this minimum standard is below the "ideal" amount for a dog.

Carbs are a bit more tricky for dogs (and cats). While dogs are omnivores and require more than just plain protein to sustain themselves, they get the required vitamins and minerals mainly from proteins and fats. In the wild, dogs and wolves would often consume the contents of an herbivore's stomach, thus providing them with a small boost of fiber and energy. In formulated dog foods, carbs can come for any number of sources such as corn, wheat, soy, peas, carrots, etc. added by the manufacturer.

Dogs do not contain an enzyme in their saliva called "amylase". Amylase is needed to completely break down carbohydrates in order to obtain all of the vitamins and minerals contained within. While they can digest carbs in their stomach, they receive minimal nutritional value from veggies in comparison to true omnivores such as ourselves. This means that while the bulk of the vegetables and starches in your dog's food can be utilized for energy and fiber, they're not gaining too much more than that. In this way, those added fruits and vegetables end up being mostly filler and bulk to prevent loose stools.

As such, AAFCO does not publish a minimum amount of carbs or fiber for dog food. Instead, they provide a minimum for all required vitamins and minerals.

Finally, there is moisture. While AAFCO does not provided a set minimum of moisture content for dogs, without water, they would grow dehydrated! Wet foods do contain a larger amount of crude moisture than dry food, but dogs receive a large majority of their moisture from their water bowl.

AAFCO Nutritional Standards Based On % or mg/kg and IU/kg of Dry Matter
Without the Breakdown of Individual Fats and Proteins
From The 2014 Official AAFCO Publication
Nutrients Growth and Reproduction (min) Adult Maintenance (min) Maximums
Crude Protein 22.5 18
Crude Fat 8.5  5.5
Calcium (Ca) 1.2 0.5 1.8
Phosphorus (P) 1 0.4 1.6
Potassium 0.6 0.6
Sodium 0.3 0.08
Chloride 0.45 0.12
Magnesium 0.06 0.06
The following are based upon mg/kg or IU/kg:
Iron 88 40
Copper 12.4 7.3
Manganese 7.2 5
Zinc 100 80
Iodine 1 1 11
Selenium 0.35 0.35 2
Vitamins & Other
Vitamin A (IU) 5000 5000 250,000
Vitamin D (IU) 500 500 3,000
Vitamin E (IU) 50 50
Thiamine 2.25 2.25
Riboflavin 5.2 5.2
Pantothenic acid 12 12
Niacin 13.6 13.6
Pyridoxine 1.5 1.5
Folic acid 0.216 0.216
Vitamin B12 0.028 0.028
Choline 1360 1360

Cat Food

Cats are metabolically strange, (which is partially why they are far more susceptible to toxins that we otherwise tolerate). While we are able to produce many of our nutritional needs by breaking down and utilizing certain things in our diets, cats are unable to produce several on their own, (most notably taurine, Vitamin A, and lysine).

Cats are obligate carnivores. This means that the amount of protein and fat required to survive is far higher than the human or canine equivalent. Like dogs, they lack the enzyme amylase in their saliva, but they also obtain the bulk of their energy from the fat in their diets. Large quantities of carbs in your kitty's diet will only go straight to their waistline. Due to these differences, cats have vastly different dietary profiles, though the order of importance is roughly the same.

Protein is by far the most important thing in a cat's food. An average cat requires between 220-350 calories per day. 25-40% of those calories should come from a protein source. This is slightly more than double the amount needed by a dog. AAFCO requires a minimum amount of 26% protein for adult felines, and 30% for kittens and pregnant/lactating queens.

Again, fats come next in the hierarchy. As cats acquire their essential fatty acids and energy from fats, the AFFCO minimum is 9% for felines in all life-stages.

Through evolution, cats instinctively have a low thirst drive, stemming from the dry, desert habitat where their ancestors originated. This means that moisture content is far more important to a cat than it is to a dog. While there is not set minimum for moisture in a cat's diet, this is often why canned or moist food diets are recommended over dry food when it comes to feeding a feline.

Much like dogs, AAFCO does not report a minimum for carbs in a cat's diet, and instead reports the necessary minimum amount of required nutrients. It's always a good idea to take a look at the carb analysis on a bag of cat food. Some food companies will put nearly half of the food content into carbohydrates such as starches and vegetables. For a cat who puts on pounds from eating too many carbs, this is far too much. Seek out food with a minimum amount of carbs for your kitty.

AAFCO Nutritional Standards Based on % or mg/kg and IU/kg of Dry Matter
Without the Breakdown of Individual Fats and Proteins
From The 2014 Official AAFCO Publication
Nutrients Growth and Reproduction (min) Adult Maintenance (min) Maximums
Crude Protein 30 26
Crude Fat 9 9
Calcium (Ca) 1 6
Phosphorus (P) 0.8 0.5
Potassium 0.6 0.6
Sodium 0.2 0.2
Chloride 0.3 0.3
Magnesium 0.08 0.04
The following are based upon mg/kg or IU/kg:
Iron 80 80
Copper (extruded) 15 5
Copper (canned) 8.4 5
Manganese 7.6 7.6
Zinc 75 75
Iodine 1.8 0.6 9
Selenium 0.3 0.3
Vitamins & Other
Vitamin A (IU) 6668 3332 333,300
Vitamin D (IU) 280 30,080
Vitamin E (IU) 40 40
Thiamine 5.6 5.6
Riboflavin 4 4
Pantothenic acid 5.75 7.75
Niacin 13.6 13.6
Pyridoxine 60 60
Folic acid 0.8 0.8
Vitamin B12 0.020 0.020
Choline 2400 2400
Vitamin K 0.1 0.1
Biotin 0.07 0.07
Taurine (extruded) 0.1% 0.1%
Taurine (canned) 0.2% 0.2%

Wet Pet Food

Even though AAFCO Reports minimums based on percentage of a nutrient per dry matter,  pet companies print food labels based on the diet percentage "as fed". For dry food with only a small added moisture (which is the majority of dry food brands - these hover around 10%), this will not make too much of a difference in the numbers AAFCO requires versus the numbers you see. However, in a wet food, there may be as much as 75% water added into the dry matter. Because the label reports what's in the entire can as opposed to what's in the "dry matter" of the can, (such as the meat chunks, veggie chunks, etc), the water will "dilute" the value of the dry matter in the guaranteed analysis. This can make the minimums on a can of wet food appear artificially lower than they are.

A great way to calculate the "true" percent of something on a wet food can is to calculate the amount given "as fed" by the amount of dry matter in the can if moisture were removed.

For Example: A can of wet adult cat food reports that it has 75% moisture and minimum of 9% protein by guaranteed analysis. Since we know that adult cats require a minimum of 26% protein by AAFCO standards, this appears far too low. However we can find the correct amount by comparing the "as fed" analysis to the actual dry matter in the can. Since we know that there is 75% moisture in the can, this means that there is 25% dry matter (100%-75%=25%).

9% protein/25% dry matter or 0.09/0.25 = minimum of 0.36 or 36% protein

We can then conclude that the can of wet food has 36% protein at the minimum in its dry matter, which is far above the 26% minimum for an adult cat. So the above food would meet AAFCO standards.

Can Packaged Foods Contain Toxins?

Now that we know what a good food for a dog or a cat looks like and can pick it up on the shelves, we're ready to delve into the real concern, which are the standards set out by the FDA, and what can end up in your bag of cat food. Let's talk about the risk of toxic exposure in pet food.

References & Notes

About The Author: Erin Clifford, CVT

Author Erin Clifford CVT

I knew from a young age that I wanted to be a cat when I grew up. When I learned that no amount of crawling on my hands and knees would make that happen, I decided I wanted to work with animals instead. Since graduating from Bel-Rea, I have worked in general practice, orthopedics, surgical rehab/therapy, and toxicology. I have published toxicological profiles through peer-reviewed journals such as VSPN and NAVTA, and I currently own and run a blog on animal poisoning for pet owners at In my free time, I love to read, write, draw, and play with my four cats and my dog.