Dog Cancer Diet

Jennifer Coates, DVM
By Jennifer Coates, DVM on Oct. 30, 2023
A dog sniffs at a bowl of food.

After a cancer diagnosis, pet parents understandably want to do everything to help their beloved pup feel better.

Fortunately, there’s a lot you can do nowadays. Advances in surgery, chemotherapy, radiation therapy, immunotherapy, and palliative care have been developing quickly, but don’t overlook the importance of nutrition—a vital part of treatment for any dog with cancer.

Cancer Diagnosis in Dogs: What’s Next?

Treating cancer takes a team. Some primary care veterinarians have training and experience in certain types of cancer, but often your “regular” vet will refer you to a board-certified veterinary oncologist for specialized care.

Pet parents who are looking for a second opinion can also make an appointment directly with an oncologist without a referral. There are even resources that have a search feature that allows you to find a veterinary oncologist near you.

However, the most important member of your dog’s care team is always you.

As their parent, you’re on the front lines, ensuring that your dog gets to do the things they’ve always loved. This includes their diet—it’s important that your pup eats well as they go through treatments and their condition changes over time.

Why Do Dogs With Cancer Need a Special Diet?

Cancer changes a dog’s metabolism.

One important phenomenon to understand is the Warburg Effect.

Cancer cells prefer to use carbohydrates (especially glucose, a simple type of sugar) as an energy source, and they produce lactate as a waste product during this process. The cancer patient must then convert lactate back to glucose, which requires energy that may be in short supply if a dog isn’t eating well.

Dogs can also experience cancer cachexia, which involves the loss of body fat and muscle, even when a dog is eating what would normally be a good diet for them.

Cancer cachexia makes dogs weak and may worsen their response to treatment. Unfortunately, the metabolic changes associated with cancer can continue even after a dog’s cancer has gone into remission.

Just as importantly, a dog’s appetite can undergo major changes after a cancer diagnosis.

The disease itself can lead to a poor appetite—particularly if the dog’s gastrointestinal tract is directly affected—but cancer treatment can be to blame as well.

For example, most chemotherapy medicine targets rapidly dividing cells because that’s how cancer cells behave.

Unfortunately, the cells lining the gastrointestinal tract also divide rapidly and are affected by chemotherapy, which can lead to nausea, diarrhea, vomiting, and a poor appetite.

A dog’s appetite can undergo major changes after a cancer diagnosis.

How to Adjust Your Dog’s Diet

Talk to your veterinarian or veterinary oncologist about what food you should offer your dog.

If your dog is eating their current diet well and it’s providing them with the nutrition they need, no change may be necessary.

However, switching foods for dogs with cancer may be beneficial at times.

Cancer-fighting foods for dogs have to satisfy several requirements:

  1. Most importantly, dogs have to eat it and enjoy it! No tumor-shrinking food or dog cancer supplement will be beneficial if dogs won’t eat it. The last thing pet parents should be doing during a dog’s cancer treatment is forcing them to eat.

  2. These foods must meet all a dog’s basic nutritional needs. Over-the-counter dog food cancer options should follow the standards of the Association of American Feed Control Officials (AAFCO).

  3. There are no hard-and-fast rules regarding the right nutrient profile of a dog food for cancer, but recommendations like these are common:

  • Protein: 30% to 40% after water is removed on a dry-matter basis

  • Carbohydrates: less than 25% on a dry-matter basis

  • Fiber: more than 2.5% on a dry-matter basis

  • Fats: 25% to 40% on a dry-matter basis

Always make changes to your dog’s diet slowly.

Take a week or two and gradually mix increasing amounts of the new food in with decreasing amounts of the old food.

This can help your dog adapt to their new diet and prevent problems like food refusal, diarrhea, vomiting, and pancreatitis

What To Do if Your Dog Won’t Eat

Sometimes a dog with cancer won’t eat or won’t eat enough—no matter what diet you try. As a result, they start losing weight. Try some simple home remedies first to help your pup, including:

  • Go back to a favorite old food

  • Try something new that you think your dog might love

  • Add a delicious food topper

  • Warm up wet food to around 100 degrees Fahrenheit

  • Offer small meals approximately every four hours

  • Try hand-feeding

If none of this works, talk to your veterinarian.

Dogs with cancer shouldn’t go more than 24 hours without food.

Your veterinarian can recommend appetite stimulants and anti-nausea medications and discuss the option of placing a feeding tube, if needed.

How To Create a Diet for Your Dog With Cancer

Your veterinarian or veterinary oncologist is in the best position to recommend good food options based on your dog’s specific needs.

They may advise that you continue feeding your dog’s regular diet, or perhaps that you switch to a therapeutic diet like a recovery diet or a food designed specifically to help dogs with cancer.

Natural Dog Food vs. Commercial Dog Food

Home-prepared natural dog foods can be a good option for some dogs with cancer, particularly those who have a very poor appetite. A dog cancer diet recipe can include ingredients that your dog loves most.

However, pet parents have to pay extremely close attention to how they cook for their dogs with cancer. Most dog cancer diet recipes you can find online or in books are not nutritionally complete and balanced, so it’s always best to work directly with a veterinary nutritionist.

Your local veterinary college,, and are all excellent resources.

Once you are sure you have a good recipe, follow it closely and ensure you cook any meat thoroughly.

The bacteria and other pathogens (like parasites) that are often present in raw meat are especially dangerous to dogs with cancer who are often immunocompromised.


Good recipes for home-cooked foods for dogs with cancer will include vitamin and mineral supplements, but vitamins and minerals should be present in appropriate amounts in any commercially available dog food you purchase, so don’t add more.

The same applies to antioxidants. They can be beneficial in some instances, but too much may be dangerous for cancer patients.

One supplement that is often recommended for dogs with cancer is fish oil, which is a wonderful source of the omega-3 fatty acid docosahexaenoic acid (DHA).

DHA has been shown to have anti-tumor effects for many different types of cancer.

The correct dose for the supplement will depend on whether any is already present in a dog’s food, but many cancer specialists recommend a total dose of 30 mg/kg/day (13.6 mg/lb/day) or around 5% of the dried-food diet.

Talk to your veterinarian or veterinary oncologist before purchasing products that are advertised as dog cancer supplements or tumor-shrinking foods.

Some may work, while others can be dangerous for your pup. Veterinarians who are familiar with your dog’s needs are in the best position to recommend supplements and foods that will be safe and effective.

Featured Image: FatCamera/iStock / Getty Images Plus via Getty Images

Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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