Controlled Weight Loss

January 22, 2026

When to Consider a Therapeutic Diet For Your Cat

Dr. Jamie Wells, DVM

It is estimated that half of pet cats visiting the veterinary office are overweight or obese, putting them at higher risk for conditions like diabetes mellitus and osteoarthritis. The first step towards a healthy feline waistline involves diet modification, but it can be overwhelming to choose the appropriate food for your cat’s diet while you are bombarded with colorful labels, slogans, and even television commercials. A therapeutic weight loss diet might be just what your cat needs to kick-start their weight loss journey.

What Is a Veterinary Therapeutic Diet?¹

Veterinary therapeutic diets are research-backed pet foods used to treat or prevent disease; they require a prescription from your veterinarian. Specific therapeutic diets may be prescribed to treat allergies, dissolve or prevent formation of bladder stones, slow the progression of kidney and heart disease, aid pets with seizures or cognitive decline, support joint health, or promote weight loss. They often come in both traditional dry kibble and wet food varieties, usually in several flavors. Due to the extensive research required to develop and formulate these diets, they are often slightly more expensive than over-the-counter pet foods. They are usually purchased from veterinary offices, but they may also be purchased from a pet food store or online retailer (and with potential cost savings) with proof of prescription.

Why Is a Prescription Required to Purchase These Diets?²

In the United States, the Association of American Feed Control Officials (AAFCO) publishes minimum and maximum nutrient requirements which must be met in order for a pet food company to claim that the diet is complete and balanced. The requirements differ between adult animals and growing animals. If you look at your pet’s food bag, you may find a statement which reads “X cat food is formulated to meet the nutritional levels established by the AAFCO cat nutrient profiles” or “Animal feeding tests using AAFCO procedures substantiate that X cat food provides complete and balanced nutrition.” These statements inform the consumer whether the diet was simply formulated to meet basic nutrient requirements, or if the diet was tested on actual pets to ensure its safety.

The AAFCO nutrient profiles specify the appropriate amount of protein, fat, vitamins, and minerals based on studies showing what is required to support health in the general pet population. Therapeutic diets often differ in nutrient profile and may not meet AAFCO minimum nutrient requirements or may exceed maximum nutrient requirements. For example, diets for pets with chronic kidney disease often have reduced protein and phosphorus content in order to slow progression of disease. While a great treatment option for pets with kidney disease, these diets would not be appropriate in healthy pets and could even lead to serious illness. For this reason, therapeutic diets require a prescription from a veterinarian.

How is a therapeutic diet formulated to help my overweight/obese cat lose weight?^2,3

Overweight and obese pets require a caloric deficit in order to lose weight, which necessitates intake of a smaller volume of food. Using traditional diets, your cat may require a much smaller volume of food compared to a cat at ideal body weight. However, when you restrict the calories and therefore the volume of food, the total amount of nutrients consumed also decreases. This means less macronutrients (carbohydrates, protein, fat) and less micronutrients (vitamins and minerals). The restricted volume of food required for weight loss in cats often does not meet daily requirements for certain macronutrients and micronutrients, which can lead to deficiencies over time.

Therapeutic weight loss diets are formulated to be light in calories but heavy in nutrients, mitigating this problem. The pet on a therapeutic weight loss diet is at lower risk of becoming nutrient deficient while eating fewer calories. Therapeutic weight loss diets are also generally higher in fiber to keep your cat feeling full. They are often also supplemented with omega fatty acids to maintain joint health and promote healthy skin. Some brands also sell combination therapeutic diets which are optimized to treat comorbidities, allowing for safe weight loss even if a pet requires a therapeutic food for another condition.

Should my pet remain on a therapeutic weight loss diet after reaching their ideal weight?

Some pets may benefit from remaining on a therapeutic diet for life, while others may transition back to over-the-counter food after reaching their ideal body condition. The decision to transition away from a therapeutic diet should take into account factors such as the pet’s metabolism and the family’s budget.

 

Sources:

1. Heinze, C. R. (2017, January 5).Much ado about therapeutic diets. Petfoodology. Retrieved from https://sites.tufts.edu/petfoodology/2017/01/05/therapeutic_diets/
2. Association of American Feed Control Officials. (2014, July 2).AAFCO methods for substantiating nutritional adequacy of dog and cat foods. AAFCO. Retrieved from https://www.aafco.org/wp-content/uploads/2023/01/Model_Bills_and_Regulations_Agenda_Midyear_2015_Final_Attachment_A.__Proposed_revisions_to_AAFCO_Nutrient_Profiles_PFC_Final_070214.pdf
3. Roudebush P, Schoenherr WD, Delaney SJ. An evidence-based review of the use of therapeutic foods, owner education, exercise, and drugs for the management of obese and overweight pets. AVMA Journals; https://avmajournals.avma.org/view/journals/javma/233/5/javma.233.5.717.xml