What to Feed a Dog with Cancer: A 2026 Guide

Why Cancer Changes Your Dog's Nutritional Needs

One of the major issues that can arise during cancer treatment in cats and dogs is malnutrition. Cancer and its treatment often have negative effects on feeding behavior and the desire to eat, including loss of appetite. Inability to consume adequate amounts of nutrients and calories can lead to malnutrition and weight loss. Cancer permanently alters the way a dog’s body metabolizes proteins, fats and carbohydrates, and significantly changes a dog’s nutritional requirements. Diet plays a crucial role in their health. Feeding a maintenance or wellness diet to a dog with cancer does not address their unique metabolic needs. Conversely, feeding a nutrition system specifically formulated for dogs with cancer can improve quality of life, decrease the effects of cancer and its treatments, and may even potentially increase survival time. Dogs with cancer need significantly higher levels of healthy fat and protein. They also benefit from a small amount of complex carbohydrates to help stabilize flood sugar. High-fat, moderate-protein, low- carb diets provide optimal nutrition for dogs with this disease.

Why a Maintenance Diet Isn't Enough

Feeding a maintenance or wellness diet to a dog with cancer does not address their unique metabolic needs. Conversely, feeding a nutrition system specifically formulated for dogs with cancer can improve quality of life, decrease the effects of cancer and its treatments, and may even potentially increase survival time. Dogs with cancer need significantly higher levels of healthy fat and protein. They also benefit from a small amount of complex carbohydrates to help stabilize flood sugar. High-fat, moderate-protein, low-carb diets provide optimal nutrition for dogs with this disease.

What Is Cancer Cachexia?

The nutritional status in dogs and cats with cancer is also negatively altered by cachexia, which is driven by systemic inflammation as a result of the cancer disease process. Cachexia differs from simple starvation in that both protein and fat stores are lost almost simultaneously, accelerating deterioration of the clinical status.

Why Dogs with Cancer Stop Eating

The Disease Itself

Living with cancer can cause waxing and waning appetite or complete loss of appetite for various reasons. If a tumor is within the gastrointestinal (GI) tract, it may interfere with food intake and may cause trouble swallowing and digesting food, or absorbing nutrients from the intestinal tract. Additionally, cancer disease processes can cause pain, stress, nausea, or dehydration, which can reduce a pet's appetite.

Surgery, Chemotherapy, and Radiation

Surgery, radiation, or chemotherapy can also contribute to loss of appetite via changes in the sense of taste or smell, feeling pain, nausea, vomiting, constipation, or diarrhea. The time of noticeable onset of cancer cachexia may vary in dogs and cats. However, the unwillingness of the pet to eat is easily noted and is known to be the major contributor to an owner's decision to elect euthanasia. Conversely, when a pet appears to enjoy their food, pet parents have a favorable perception of their pet's quality of life.

Are Homemade and "People" Foods Safe?

There are different ways to make eating more enjoyable for the pet—offering foods and food forms the pet likes or preparing homemade or "people" foods. The drawback of feeding people foods, however, is that unless a recipe formulated by a board certified veterinary nutritionist is followed, individual people foods are not a complete and balanced food for pets and may contain ingredients that can be harmful under certain organ dysfunction (e.g., excess sodium, protein, fat or inclusion of garlic, onions, lactose). One option for owners is the palatable commercial foods designed by Hills Pet Nutrition for pets living with cancer.

How a Therapeutic Cancer Diet Is Developed

Animal nutrition scientists from Hill's Pet Nutrition initiated research on nutritional support for pets living with cancer about seven years ago. The goal was to develop complete and balanced dog and cat foods that would address the nutritional challenges of cancer patients, including the decreased interest in eating. The challenge of designing such commercial pet foods was to find the right balance between nutritional attributes of the foods and their palatability. The scientists collected and evaluated multiple information sources to understand the nutritional needs of pets with cancer. This included gathering insights from pet parents and veterinary healthcare team members, including board certified specialists in oncology, nutrition, and feline medicine. Based on all the received input, and after reviewing the most current published evidence, scientists formulated and created Hill's Prescription Diet ONC Care. Alongside providing essential nutrients and energy, the fiber and active biome content help to eliminate chemotherapy induced diarrhea.

How to Get a Dog with Cancer to Eat

If your pet is struggling to eat their food, try these suggestions one at a time from the top of the list, or you may combine them, if needed: Heat the food before serving. This will increase the aroma and may make the food more enticing. Replace the water with low sodium chicken or beef broth or bone broth. Boil the broth and pour it over the food and stir, then mix in the supplements and salmon oil. Let the mixture sit for at least 20-30 minutes before feeding. Mix in one or more of the following: 1–2 Tbsps. cheddar, ricotta or cottage cheese 1–2 tsps. diced ham 1–2 Tbsps. liquid from can of tuna in spring water 1–2 Tbsps. canned tuna packed in spring water ½ to 1 scrambled, chopped or hard-boiled egg 1 tsp. peanut butter mixed with warm water, drizzled over the food. Caution: Make sure the peanut butter does not contain xylitol which is toxic to dogs. 1–2 tsps. chopped bacon 1–2 tsps. chopped anchovies

When to Call Your Veterinarian

Sometimes hand feeding or sitting nearby on the floor while your dog is eating is helpful. Many dogs experience periods of inappetence when they are ill. If these suggestions do not help, please consult your veterinarian or oncologist. Important: Please do not try any foods on this list if your dog has dietary restrictions or health conditions (e.g., kidney disease, pancreatitis) that would preclude these suggestions, or if they contradict recommendations from your dog's veterinarian.

Reference

Anthony RM, Amundson MD, Brejda J, Becvarova I. Acceptance of a Novel, Highly Palatable, Calorically Dense, and Nutritionally Complete Diet in Dogs with Benign and Malignant Tumors. Veterinary Sciences. 2023;10(2):148. doi:10.3390/vetsci10020148