Therapeutic diets

Sometimes, when a pet has a medical condition or chronic disease, it can be managed with a diet change. Amazing, right? Scientists and board-certified veterinary nutritionists have developed special pet foods that act like medicine for your pet; these foods are known as therapeutic diets. Therapeutic diets are a truly remarkable advancement for pet health and veterinary care!

What is a therapeutic diet?

Therapeutic diets are pet foods designed to be fed as the sole diet for pets with specific diseases or medical conditions. They can act similarly or complementary to medications or drugs, and they are therefore used to treat or prevent disease in pets. These diets have been developed over decades by veterinarians, animal nutritionists, and other scientists. An immense amount of scientific research goes into formulating and creating a therapeutic diet. Therapeutic diets have been proven through research and feeding trials to prevent, support, treat, or cure specific diseases.

Why do I need a prescription to buy a therapeutic diet?

Therapeutic diets fall under the FDA’s definition of a drug: “a substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease.” Even though these products do not contain medication, they are still drugs in the sense that their purpose is to treat specific medical conditions. Something else they have in common with drugs is that they may not be appropriate for normal healthy pets. Therefore, the FDA regulates therapeutic diet production, labeling, and distribution. One of the FDA’s many requirements for therapeutic pet diets is that they must be “made available to the public only through licensed veterinarians.” The prescription or authorization from a veterinarian is in the pet’s best interest, to make sure that the appropriate diet is being fed to manage the disease, and the pet is being monitored correctly throughout the process. Veterinarians do not receive “kickbacks” from Big Pet Food for recommending these products; learn more at Veterinarians and the pet food industry

You should see this type of terminology on the label:

Some over-the-counter pet foods contain claims that they can treat or prevent disease in pets. These products are “misbranded,” meaning they have not been approved by the FDA and are not proven to treat disease. Unless they include a specific disclaimer* on the label, the companies who produce these diets can be subject to legal action by the FDA. However, it is difficult for the FDA to enforce labeling since there are so many pet foods on the market.

Beware of “veterinarian-approved” or “veterinary” diets that are available without a prescription from a licensed veterinarian. These diets are not regulated by the FDA and are not approved to treat or prevent disease.

Beware also of therapeutic or veterinary diets made by companies outside the USA. These companies do not have to adhere to the FDA’s policies and therefore are not the same quality as diets developed and manufactured in the United States.

Who makes therapeutic diets?

Very few pet food companies have the expertise, facilities, and funding to produce therapeutic diets. These companies employ board-certified veterinary nutritionists, perform scientific research and feeding trials, and uphold stringent quality control. These companies are registered as drug manufacturers with the FDA, and their facilities are regulated by the administration as well. Their therapeutic diets must be proven effective for treating or preventing disease in animals. All of these factors add to the expense of therapeutic diets: it costs a lot to employ experts, develop these diets, and meet all the FDA’s regulations.

For more information on finding reliable pet food manufacturers, visit How to pick a pet food, part 1.

Types of therapeutic diets

There are many therapeutic diets out there. Each diet is designed to help manage one or more specific diseases in dogs or cats. If your pet has a health issues, their usual veterinarian should be able to diagnose their condition and provide you with a therapeutic diet that meets their needs. There are diets for conditions not listed below, but these are the most common.

Renal diets

These diets are used to treat kidney disease in both dogs and cats. They contain very low phosphorus, a mineral that can build up in the blood when there is kidney damage and cause problems in the body, even making the kidney disease worse. They also contain a moderate amount of protein because compromised kidneys have a tough time filtering these large molecules. Sodium levels in these diets are also low, and they may contain therapeutic levels of Omega-3 fatty acids. Renal diets are highly palatable and have high calorie density, which promote eating and combat weight loss. They also have high levels of B vitamins, which are excreted in the urine. 

Obesity diets

These diets are designed to help cats and dogs lose weight. They contain high fiber, which helps them feel full and therefore eat less. They also have very low calorie density, meaning they have fewer calories per cup or gram compared to other diets. They have high proportions of other nutrients to balance this out, so that pets eating these low-cal diets do not develop nutrient deficiencies.

Thyroid diets

These diets are used to treat hyperthyroidism in cats. They contain very low levels of iodine, a mineral that is necessary for the production of thyroid hormone (thyroxine). Cats with hyperthyroidism produce too much thyroxine, so the iodine deficiency caused by these diets helps lower production of this hormone.

Diabetic diets

These diets are used for the maintenance of diabetes in dogs and cats. They may contain very high insoluble fiber levels, which slows emptying of the stomach and reduces blood sugar spikes. The high fiber also contributes to satiety (feeling full) and aids with weight loss, which is especially important for diabetic cats. Another type of feline diabetic diet is low carb/ high protein, which helps manage insulin levels through a different metabolic pathway. 

Hydrolyzed diets

These diets are used to diagnose and treat food allergies in dogs and cats. Allergies are almost always due to a protein source, so the proteins in truly hypoallergenic diets are hydrolyzed, or broken down into tiny particles called amino acids and peptides. These particles are so small, the pet's immune system doesn't recognize them, and they therefore do not cause an allergic response. For more information, visit Food allergies.

Urolith diets

These diets are designed to treat and prevent certain types of bladder stones and crystals in dogs and cats. There are several different types of bladder stones, and each is managed differently. Some stones can be dissolved in the bladder just by changing the pet’s diet, allowing them to avoid surgery. Diets for the treatment and prevention of bladder stones may change the acidity of the pet’s urine, reduce intake of minerals that make up these stones, and increase the pet’s water consumption. Once a pet is diagnosed with bladder stones by a veterinarian, they will usually eat the urolith diet for the rest of their life, as it will both treat current problems and prevent them from reoccurring in the future.

Dental diets

These diets are designed to treat and prevent plaque buildup and calculus (tartar) development on the teeth of dogs and cats. The kibbles are hard, large, and uniquely shaped, requiring that the pet chews thoroughly before swallowing. This chewing motion is proven to remove tartar and prevent plaque buildup. (To learn more, visit The importance of oral health.)

Gastrointestinal diets

These diets are designed to be easy on the digestive system of both dogs and cats. They typically have controlled fat levels, highly digestible protein, and may be supplemented with Omega-3 fatty acids or other nutrients. These diets are usually used in management of digestive diseases such as pancreatitis or diarrhea.

Recovery diets

These diets are designed for dogs and cats who need nutritional support while they are in the hospital. They are energy-dense, meaning they have more calories per gram than typical diets. They are also highly digestible, have lots of protein to prevent muscle loss, and are highly palatable to pets in critical care settings. Recovery diets are made in a canned or liquid form, so they are easy to administer to hospitalized patients through feeding tubes. 

Joint diets

These diets are used to treat arthritis pain in dogs. They contain therapeutic levels of Omega-3 fatty acids, nutrients that decrease inflammation and supply nutrition to the joints. They may also contain high levels of supplements like glucosamine, chondroitin, and/or green-lipped mussel.

What if your pet needs a therapeutic diet?

If your pet has been prescribed a therapeutic diet, you’ll want to be sure to follow all the veterinarian’s instructions regarding feeding and medicating. Some pets will still require medications even when on a therapeutic diet, while others might not. Sometimes, a therapeutic diet must be fed exclusively, meaning no people food, over-the-counter treats, or flavored medications. Often, therapeutic diets are not safe for healthy pets, so you’ll want to keep your pets separate during feeding times. Be sure to ask your pet’s usual veterinarian what they recommend regarding the above. And of course, be sure to bring your pet to the veterinarian regularly for checkups and to renew their diet prescription. Routine exams, bloodwork, and urinalysis is important for managing most conditions, and they also help the veterinarian determine if the diet is effective.

Alternatives to therapeutic diets

There are a few alternatives” to therapeutic diets, some of which are generally safe, and some that may be unsafe.

Safe alternatives


Often, therapeutic diets are chosen because they can help avoid or reduce the use of drugs needed to treat a disease. Still, many chronic health conditions will require a combination of medications and a therapeutic diet. If a therapeutic diet is not an option, however, an effective alternative to using a therapeutic diet may be prescription medication. Your pet’s usual veterinarian will be able to advise you on the best course of action for your pet’s specific case.

Homemade diets

Sometimes, pet parents may choose to go the homemade route when their pet has special dietary requirements. This is especially true when a pet has more than one medical condition, and there are no therapeutic diets that fit their needs. If you choose to go the homemade route, be sure to work with a board-certified veterinary nutritionist. These experts are the only ones qualified to formulate a homemade therapeutic diet for your specific pet. For more information, visit Homemade diets.

Unsafe alternatives


Supplements are not regulated well by the FDA or AAFCO. Attempting to balance or alter a diet without the assistance of a board-certified veterinary nutritionist can be very dangerous for your pet. Supplements have not been proven to treat or cure disease, so they should never be used to manage disease on their own. However, some supplements may contain nutrients (such as Omega-3 fatty acids) that may help the body recover from or fight disease. Ask your veterinarian before you purchase any supplements or food additives, as they may not benefit and may even harm your pet. (To learn more, visit Supplements.)

Raw diets

Raw meat-based diets are not safe for pets with health conditions. They contain pathogenic bacteria and parasites that can cause severe illness in immunocompromised pets. Additionally, due to their uncooked nature and nutrient profiles, they can cause severe digestive upset. Raw diets can also make certain disease processes much worse. Never feed raw products to pets with medical conditions. To learn more, visit Raw diets.


This article is intended to be informational; it is not an advertisement for any products or diets. The author is not paid to promote any products or diets mentioned in this article. The author is not a salesperson, nor is she employed by any pet food companies.