Choosing the right food for your dog or cat

Animal Humane Society digs in to trending topics on pet food

Dog eating food

If you’ve ever wondered whether you’re feeding your pet the right food, you’re not alone. It’s a big decision! Google responds to millions of searches about pet food every month. And if you’ve paid attention to recent news, the pet food industry (which pulled in more than $32 billion last year) is reeling over scientific links between grain-free food and canine heart disease.

Keeping up with changing diet fads and seemingly countless food options can be confusing and overwhelming. To make things more complicated, every pet owner seems to have an expert opinion.

What you feed your four-legged family member is just as important as what you feed your own body. There’s a lot to consider, including ingredients, brand reputation, and cost. So Animal Humane Society’s chief veterinarian, Dr. Graham Brayshaw, is here to break down what you need to know to make an informed decision.

First things first: understanding your pet's digestion system.

The basics of cat nutrition

Cats are carnivores at heart. Their basic needs include food that is 40-45% protein, high in fat, and contains few carbs. (You can feed your cat grains, but they lack the digestive enzymes to break them down, so there’s no real nutritional benefit.)

Cats don’t create some of the internal amino acids that dog and human bodies do, so it’s critical that taurine, an amino sulfonic acid, is added to their diet. Without taurine, cats develop Dilative Cardiomyopathy — a condition where their heart grows larger than normal and has to work extra hard to function. 

Taurine is naturally found in most meat and fish, but can be stripped during food processing. It’s especially sensitive to heat, and is mostly destroyed in cooked meat. Commercial cat food includes taurine, but dog food doesn't — so cats need food specific for their nutritional needs.

If you’re preparing and cooking your cat’s food at home, you’ll need to add it as a supplement. 

The great debate: Wet food vs. dry food

Canned food is often seen as the holy grail of cat food options. Just because some cats go crazy for it doesn’t mean it’s the only option to consider.

Canned food can help keep your cat hydrated (hydration is a key component in your kitty’s kidney and bladder health). Approximately 80% of canned food is water, which can help if your cat doesn’t drink much on their own. 

Canned food can’t be left out all day like dry food. It will congeal, and your cat might not eat it after it’s been sitting out. It’s also more expensive. If you don’t have much room in your budget, dry food may be the way to go. 

Dry food is great for maintaining feline dental health. The kibble scrapes against their teeth when they chew and naturally removes plaque. If you feed your cat canned food only, you should brush your cat’s teeth regularly to avoid dental issues. 

The takeaway: Although canned food may be the healthier option, feeding your cat dry food has its unique benefits too. 

The basics of dog nutrition

Dogs and humans have similar gastrointestinal tracts and require similar types of food. Just like us, dogs are omnivores and eat meat as well as greens and grains. It's a misconception that dogs need meat only — they require other nutrients too.

It's always a good idea to look at the ingredients in your pets' food. Two main nutrients to look for are protein and fats. When shopping for dog food, look for at least 18% protein, as it's a critical part of a well-balanced dog diet. Healthy amounts of fat are specific to each dog. Breed and lifestyle can dictate how much fat is too much. Check with your veterinarian to be sure what's best for your pup.

While you can give dogs a non-meat diet (yes, dogs can be vegetarians!), take extra care to provide them with enough protein, fat, and additional nutrients they would normally get from meat. 

Grain-free dog food

With grain-free food falling out of style following a 2018 FDA warning, you might be slightly panicked about what this means for your four-legged friend. It’s true that some dogs on a grain-free diet were found to have heart disease, specifically Dilative Cardiomyopathy. If your dog has been eating grain-free for years don’t worry. They aren’t likely to have problems with their heart unless you’ve already noticed symptoms. Switch food if you’d like, but if they’re happy and healthy on their current diet, talk to your veterinarian about whether or not you should change it.

The current understanding in the veterinary community is that dogs are able to digest grains normally and there is usually no reason for a grain-free diet. Research is still digging into why the food causes the disease, but has found that switching dogs with this type of Cardiomyopathy off of grain-free food improves their heart function.

If your dog is sensitive or allergic to a specific type of grain, look for a food with a different source of grains. There are plenty of options like brown or wild rice, quinoa, corn, wheat, and barley.

(Read on to find out the difference between an allergy and sensitivity.)

The basics of rabbit and rodent nutrition

Rabbits, Guinea pigs, rats, and other rodents are hindgut fermenters and require a much different diet than other pets. They have a sac at the division of their small and large intestine called a cecum — a vat of bacteria to digest the high-fiber food they eat. When they eat hay, the bacteria in the cecum ferments the hay and turns it into small pellets call cecotropes. Rabbits and rodents pass the cecotropes and eat them again so that nutrition isn’t lost and is instead absorbed through the small intestine. Because of their unique digestive system, these critters need to eat large amounts of fibrous plants.

Additionally, Guinea pigs can’t produce Vitamin C on their own and need to receive plenty through the food they eat.

Cat eating food

Look for AAFCO statements on your pet's food

One easy way to check if your pet's food is safe and healthy is to look for certification from The Association of American Feed Control Officials (AAFCO). If the food is considered to be a complete diet by AAFCO, it'll have one of two statements under the ingredients list:

  1. This product is formulated to meet the nutritional levels established by the AAFCO Dog Food Nutrient Profiles.
  2. Animal feeding tests using AAFCO procedures substantiate that this product provides complete and balanced nutrition.

The difference between the statements is that food with the second statement has gone through testing and feeding trials to prove the food meets nutritional standards, but both indicate good, healthy food.

Large brands like Purina One, Science Diet, and Royal Canin have all been tried and tested. So while it may be tempting to switch to the newest food that claims to be healthier or better for your pet, be sure to look for the AAFCO certification. Otherwise it likely hasn't been around long enough to go through the proper testing and diet trials to prove those marketing claims.

What about popular diets or special cases?

Food allergies

Before we dive into food allergies, it's important to note that there's a big difference between food allergies and food sensitivities.

  • Food allergy: The immune system has a full body reaction to something it's encountered. When a human is allergic to bee stings, their whole body has symptoms like swelling, redness, nausea, and vomiting.
  • Food sensitivity: An upset stomach or stomach-related symptoms due to eating certain foods. You might experience a sensitivity to lactose when you drink milk or eat ice cream. It’s bothersome but not life-threatening.

Dogs and cats that have food allergies usually have skin-related symptoms. You might see a skin infection or hair loss around their ears, back, mouth, or rear-end. Fortunately, food allergies aren't common. Out of all dogs with allergy-based conditions, only about 10% are caused by food. Most are environment-related, like grass, pollen, or mold.

If you see these symptoms in your pet, try switching the main protein source in their food first. 

A diet trial can help find the source of the allergy, but it's a time consuming endeavor. It takes 12 weeks to heal from an exposure to a food allergen. And it might take several rounds of trying different foods to determine which ingredient an animal is allergic to.

Cute rabbit

Luckily, there’s another option to help pet parents who can’t figure out which ingredient in their pet food causes issues — Hydrolyzed (HA) food. It’s cooked at a high temperature to break down the proteins so they no longer cause an allergic reaction.

Prescription diets

While you don't need a prescription from a veterinarian to buy prescription pet food, you do need to buy the actual food from a veterinarian's office. This simply ensures people aren't giving specialized diets to their animals that don't need them.

These foods can be expensive and are likely not AAFCO certified, but they're necessary for some animals.

  • Kidney disease: Prescription diets were developed with kidney disease in mind. The increased salt content helps flush water through the kidney and bladder, reducing or preventing kidney stones. Prescription food can significantly increase a cat or dog’s life span.
  • Diabetes: Insulin is necessary to treat the diabetes, but a specialized diet can reduce or eliminate the need over time and help maintain the disease.

Prescription food plays an integral role in some animals' lives, but should only be purchased with the guidance of a veterinarian.

Dog with food

Raw diets

A raw diet can be incredibly nutritious for your pet if done right. Traditional, commercial dry food is only 80% digestible, where home-cooked and raw food is up to 98% digestible. A lower digestibility is not harmful to your pet, it’s just simply less efficient.

If you’re thinking about making the switch to a raw diet for your pet, remember that you’ll need to replace all nutrients with raw proteins, fats, and carbs. Animals eat the majority of the animal when they hunt — that means you need to feed your pet more than just chicken breast. They need all kinds of animal parts, bone, grains, and greens. Additional supplements can be helpful to round out a meal, but check with your veterinarian to make sure you choose ones that are healthy.

Raw diet risks:

  • Calcium and phosphorus are important minerals that help with bone density and kidney health. But too much bone or meat in a diet can lead to an over-abundance of these minerals, throwing your pet’s nutrition off balance.
  • Because you’re not cooking your pet’s food, any bacteria on the food can transfer to your pet, yourself, or your family. Even if you’re diligent about cleanliness, feeding your pet raw food increases the likelihood of having bacteria like Salmonella in your home.

A raw diet can be a wonderful option for your pet as long as you balance the health risks with what’s best for your pet and your safety.

Cat with food

What to consider when selecting pet food:

  • The specific nutritional needs of your pet
  • AAFCO certification
  • Your time and resources
  • Your own food bias
  • Special medical needs
  • Expensive doesn't mean the food is better
  • Breed-specific diets aren't always the best choice

Dry matter basis

Dry matter basis is another important factor to consider as it changes how nutritious the food is.

Taking water of out the equation allows you to compare dry food to wet food.

  • Dry food: Up to 10% water
  • Semi-moist: Up to 30% water
  • Canned food: Up to 80% water

When you look at the nutrition information on pet food packaging, you’ll see carbs, fat, and protein listed. If there are 5g of fat in 100g of canned food, it seems like 5% (5g out of 100g) of the food is fat. But, when you factor in water, 80% (80g) of the 100g is water. Therefore, 25% of the food is fat (5g out of 20g). But Math isn't everyone's favorite subject.

If you have questions about what you're feeding your pets or you notice that your pet may be having food-related health issues, talk to your veterinarian.

Take Purina's Pet Food Finder Quiz

How much food should your pet be eating? How many times a day? What food is best for your specific pet? Purina’s new Pet Food Finder Quiz tool can help you be certain you’re feeding your cat or dog the best possible food for a long & healthy life! 

Sign up for AHS email

If you found this article helpful and want more information about pet parenting, sign up for email from AHS. You'll receive behavior tips, stories about adorable, adoptable animals, and more!