How to pick a pet food

part 2 - assessing the pet

Choosing a pet food is an important process, but not all pet foods are right for every pet of every breed, age, or lifestyle. Finding the right pet food is also time-consuming and should not be taken lightly! After you have chosen a reliable manufacturer (part 1), following the suggestions below will help you choose a food that is right for your pet.

The best food for your pet will meet all of his or her needs. There are many considerations you need to keep in mind, especially factors like your pet’s age, health status, body condition, and activity level. Other factors you should also consider are breed, size, and eating habits. 

Life stage

The Association of American Feed Control Officials (AAFCO) has set specific requirements on pet food labels regarding life stages. As mentioned in “How to pick a pet food, part 1,” AAFCO has a set of nutrient profiles for the dog and for the cat, and they also have profiles for different life stages within each species. This is because the nutrient requirements for young growing animals are different from mature adults. Likewise, the requirements for mature adults are different than those for pregnant or lactating mothers.

Choose a food that is labeled for use in animals who are in your pet’s life stage. (The nutritional adequacy statement can be found on the back of the food bag.) For example, if you have a puppy, ensure you are buying food that is labeled for use in growing puppies. Large breed puppies have different requirements than smaller breeds, so make sure the label specifies large breed if you own a large breed pup. If you have an adult cat, make sure the food is labeled for use in adult cats, or for “all life stages.” If you have a pregnant or lactating bitch or queen, choose a food labeled for pregnant or lactating animals.

Growing animals and pregnant/lactating mothers

Feeding your pet a food that is not designed for their specific life stage can be detrimental to their health. For example, giving puppies food designed for adult animals can result in bone deformities because the diet does not have the right amount of minerals needed for growing bones. Large breed puppies require less minerals in their diet because they are prone to growing too fast, so diets labeled for use in large breed puppies have adjusted mineral amounts so that they do not develop bone deformities from accelerated growth. 

Both puppies/kittens and pregnant or lactating mothers have an increased requirement for fat and protein in their diets. For puppies and kittens, this is because they need these nutrients for growth and development. For mothers, they need these nutrients to grow their babies and keep themselves healthy at the same time. Foods labeled for use in growing puppies or kittens, or foods labeled for use in pregnant/lactating adults, should be used in these situations to prevent growth abnormalities or birth defects.

Fawn, 15 weeks old

Intact versus neutered pets

In regards to reproductive state, sexually intact pets have higher energy requirements than spayed or neutered (“fixed”) pets because of their higher metabolism due to increased hormones. Intact animals may benefit from foods that are higher in fats and/or have more kilocalories (kcal) per cup or can of food.

Senior pets

As medicine advances and our pets are living longer than ever before, pet parents have become more interested in “senior” diets. However, there are no particular labeling or legal requirements for senior diets, because nutritionally, healthy senior pets have the same or similar requirements to mature adults. There are a few nutrients that may benefit senior pets, but so far, research does not support creating an entirely new nutrient requirement profile for them. Until more is known, be wary of “senior diets,” and find out what makes the diet senior pet–specific. Some senior diets may supplement extra fatty acids which may support joint health and cognitive functions. Others may include higher protein to help combat muscle loss, or joint supplements such as glucosamine or chondroitin. It is important to keep in mind that none of these factors have been proven to be beneficial for every aging pet, so choose with caution. If you are unsure if your pet is old enough to be considered “senior,” if you are wondering about the benefits of supplemented diets, or if your pet has a disease associated with aging such as kidney disease, please contact your pet’s usual veterinarian for more specifics on this topic.

Lucy, 14 years old

Health status

Most over-the-counter adult pet foods are focused on healthy animal maintenance. If your adult pet does not have a disease or health condition, choose a regular maintenance diet.

If your pet has a specific health condition or disease, a therapeutic diet should be suggested, prescribed, and purchased through your pet’s veterinarian. Therapeutic diets are highly regulated by the FDA because they contain a drug claim: a statement saying the diet can be used to treat or prevent a disease. Therefore, to get on the market, these diets have been licensed for this purpose. Extensive research goes into the development, testing, and approval of these products, and they have been proven to work. If your veterinarian recommends a prescription diet, it is very important that you follow this request. For some diseases, such as kidney disease or bladder stones, diet is the only way to effectively treat the animal. 

If you have a pet with a disease, forgoing these diets can be detrimental to your pet’s condition. Likewise, feeding a therapeutic diet to a normal, healthy animal may result in nutrient deficiencies in that healthy pet. For example, if you have two cats, one healthy and one with kidney disease, these cats should be eating different foods and should be fed separately at mealtimes.

Learn much more about therapeutic diets here.

Weight and body condition score

Weight and body condition, while not the same thing, go hand in hand. You should assess both of these factors when choosing a diet for your pet. For example, your pet may be a “normal weight” for their breed, but they could be shorter than average and morbidly obese. Check out How to body condition score for more information on assessing your pet’s body condition.

When choosing a pet food, take into account the calorie content of the diet. If your pet is overweight or obese, he might benefit from a diet that has a lower calorie density (i.e., has less kcal per cup), so he can eat more and feel full, but consume less calories. If your pet is underweight or too thin, he might benefit from a diet that has more fat and a higher energy density, meaning he can eat less but get more energy. These details can be found on the back of the pet food bag.

Frankie, 14lb, BCS 7/9 (overweight)

Activity level and lifestyle

Again, you will want to take into account the energy density of the diet. For very active animals, consider a food that has a higher energy density, so they can keep up with the calories they burn during their daily activities. For couch potatoes, consider a diet with lower energy density, so that they do not take in more calories than they need.

Highly active animals may also benefit from higher protein in their diets, since their muscles are subjected to more stress and need to be repaired more often. However, foods labeled "high protein" should be scrutinized, because this term has no official definition. Normal, healthy adult dogs and cats require only about 25% protein in their diets, so "high protein" could be any number above this. (There is no legal labeling requirement for the term "high protein," so diets labeled as such may not even have a higher percentage of protein.) Animals who are not highly active do not have increased protein requirements, so feeding a diet labeled "high protein" is not recommended or necessary for these pets.

Very active animals may also benefit from increased fatty acids in the diet, or diets supplemented with glucosamine and chondroitin for joint health.

Speck, red heeler, goes on 20+ mile hikes multiple times each week


Some dogs, particularly large breeds, may benefit from a breed-specific diet. Large breed dog foods generally have increased fatty acids or glucosamine and chondroitin for joint health. They may also have a higher energy density, so your dog doesn’t have to eat as much kibble to get the calories he needs.

Large breed puppies require special food; the nutritional adequacy statement should say something like this: “This diet is formulated to meet the nutritional levels established by the AAFCO Dog Food Nutrient Profiles for growth, including growth of large breed dogs (70lbs or more at adulthood).”

Dog and cat breeds with long hair or who are prone to skin issues may benefit from diets which have added fatty acids for skin and hair coat support.

Some pet food companies actually have diets which are specifically formulated for certain breeds. These diets have extensive research to back up why they are the best for each breed. Certain components taken into consideration are nutrient requirements and proportions, kibble size and shape, energy density, and other factors.

Charlie, an adult German Shepherd Dog, eats a diet specially formulated for his breed

Eating habits

Dogs or cats who eat their food very quickly may benefit from foods with larger, harder kibbles so they are encouraged to chew. They may also benefit from wet food, which can be harder for them to eat too quickly.

Picky eaters may benefit from canned food, which can be smellier and more enticing. Adding warm water to canned food or kibble can also help with temperature and smell, and cause the food to be more attractive to the pet.

Pets who scavenge your food or who are constantly begging may not feel full enough after their meals. Consider a food with a lower energy density, so that they can eat a larger volume of food while getting less kcal per cup or can. For these pets, you may also want to consider feeding smaller, more frequent meals throughout the day.

Before you begin the process of changing your pet’s food, it is important to make sure you have enough of his or her current food so you can make a smooth transition without upsetting your pet’s stomach. (Learn more at How to transition your pet to a new diet.)

When comparing diets, it may be helpful for you to write all of these factors down and see which foods have what your pet needs and which don’t. You could even make a spreadsheet of these and other factors (such as the WSAVA recommendations), and see which diet meets most of your preferences and your pet’s needs.

Choosing a pet food is never an easy process; it requires time, effort, and dedication. Make sure you are keeping both your pet’s nutritional needs and the quality of the diet in mind (see part 1), so that you can find the ideal diet for your pet!