Your dog's diet is a powerful tool to effectively manage various medical conditions

Diet for dogs with cancer

If your dog has been diagnosed with cancer and would like to book a consultation, please send us an email, and we will be happy to help you and your dog.

Updated February 2024, by Kristina Johansen

In this guide on diet for dogs with cancer, we will primarily focus on food, but I will also delve into various relevant topics such as:

  • Weight loss
  • Getting your dog to eat
  • Ketogenic diets
  • Supplements

So, let’s dive in!

My dog has cancer; what now?

No one wants to be given the news that their dog has cancer. However, if you find yourself in this situation, don’t lose hope. Every day, there are incredible treatments out there, helping countless dogs around the world beat this devastating disease – and science is making new discoveries all the time.

While a qualified oncologist and your primary veterinarian should manage medical treatments, you can contribute to your dog’s health by providing a nutritious diet. A healthy diet can boost your dog’s strength and energy, improve their well-being, speed recovery, and help them tolerate treatment and its side effects better.

Additionally, good nutrition can help your dog maintain a healthy weight and prevent or reduce muscle wasting – a condition known as cachexia.

Feeding a dog with cancer

As soon as you hear the word ‘cancer,’ you might be tempted to search online for guidance, especially when it comes to what to feed your dog. It’s understandable; cancer is a scary thing.

However, while many ‘cancer diets’ for dogs are available online, it’s important to remember that cancer affects every dog differently.  This means there’s no single ‘cancer diet’ suitable for all dogs.

Both the disease and its treatment can impact your dog’s appetite, weight, and even how their body uses nutrients and tolerates certain foods. This means that to give your dog the best chance of beating cancer, you’ll need to create a diet tailored to their specific needs and type of cancer.

With this in mind, let’s look at some key guidelines when planning your dog’s diet during their cancer battle.

Calories & nutrient content

Making sure your dog receives the right amount of calories and all essential nutrients is the top priority when it comes to diet for dogs with cancer!

If your dog has been diagnosed with cancer, one of the first things you might notice is weight loss. This is because the disease itself, along with the side effects of chemotherapy and radiotherapy, may cause muscle wasting and loss of appetite.

The good news? Feeding the right type of food can significantly impact your dog’s body condition and overall health.

The goal here is to provide your dog with foods they love while also making sure they get all the calories and nutrients they need. Doing this not only helps stabilise their weight but also prevents malnutrition.

Some calorie-rich and nutrient-dense food options that most dogs typically favour include:

  • Eggs
  • Mackerel
  • Ricotta cheese
  • Lamb
  • Beef

High-quality protein

Dogs who are fighting cancer typically require a higher amount of protein than usual. This is because protein plays a vital role in muscle growth and repair. Without enough protein, it can take longer for your dog’s body to recover from illnesses, especially after cancer treatments such as chemotherapy and radiotherapy.

However, it’s not just about the amount of protein; equally important is the quality of the protein, and that depends on the amino acids that are present. That’s why it’s essential to consider something called the Biological Value (BV) when choosing the best protein for dogs with cancer.

BV measures how efficiently your dog’s body uses protein. Proteins with higher biological values are absorbed and utilised more effectively, making them a preferred choice.

Good sources of high-quality protein include:

  • Eggs
  • Meat
  • Dairy Products
  • Fish
  • Poultry

Image of a whole egg with the headline stating 'Eggs have one of the highest Biological values of all foods


Carbohydrates are often blamed for ‘feeding’ cancer cells and helping them grow. However, the relationship between cancer cells and carbohydrates is a lot more complex than that. You can dig a little deeper into the subject by heading to this link: Do carbohydrates feed my dog’s cancer?

In short, while it’s certainly advisable to avoid foods with a high Glycemic Index (GI), it’s important to remember that carbohydrates act as fuel for everything the body does. Avoiding them completely could leave your dog’s healthy cells low on energy.

Additionally, diets low in carbohydrates often have higher fat content, which may not be ideal for every dog battling cancer and could even backfire – we’ll delve into this later.

It’s also worth noting that many carbohydrates are rich in antioxidants that can help defend cells against damage So, they’re not all bad news.

I want to make it clear that I am not suggesting a high-carbohydrate diet for dogs with cancer. You need to consider what is best for your dog’s individual needs.

Here are some good options for high-calorie carbohydrates:

  • Brown rice
  • Sweet potato
  • Quinoa
  • Whole wheat pasta
  • Oats

And here are some low-calorie options:

  • Broccoli
  • Blueberries
  • Apple
  • Carrots
  • Bell peppers


Dietary fats play a crucial role in the diet of dogs with cancer. They not only increase the food’s calorie content, but fat also tastes good, so it improves the appeal of the food. This is especially important for dogs with cancer, as the disease often affects their appetite.

Good sources of fats and high-fat foods include:

  • Olive oil
  • Coconut oil
  • Flaxseed oil
  • Whole eggs
  • Fatty cuts of beef
  • Fatty fish
  • Chicken thighs (preferably with skin)

Ketogenic diets

You’ve probably already come across the term “ketogenic diet” in your search for information on the best diet for dogs with cancer. Essentially, it’s a high-fat, low-carbohydrate diet designed to lead the body into ketosis. In ketosis, the body primarily relies on ketones, derived from fats, for energy instead of carbohydrates (glucose).

I’m a visual person, and to better communicate the idea, I created a small illustration.

an illustration showing the steps for the body to enter ketosis compared to a traditional diet

What’s the goal of a keto diet?

We know that cancer cells prefer to use glucose as their energy source. Therefore, in theory, by changing the diet to a high-fat, low-carb diet, the body will use fat for energy, while cancer cells are starved of glucose.

Is there evidence to support keto diets for dogs with cancer?

There is some early-stage evidence suggesting that ketogenic diets may be beneficial in slowing the progression of some types of cancer in dogs. However, clinical evidence is limited. Most of the research on ketogenic diets and cancer has been conducted in laboratory settings or on humans. Translating these findings to dogs is not straightforward.

Therefore, further research is needed to determine the long-term safety and effectiveness of ketogenic diets for dogs with cancer.

My two pennies’ worth

Before starting a keto diet, please consider the following:

To reach a state of ketosis in dogs, their diet must contain a high-fat percentage, often exceeding 70% of dry matter (DM). However, it’s essential to keep in mind that this approach is only suitable for some dogs.

A very high-fat diet can lead to gastrointestinal issues and even severe and life-threatening conditions like pancreatitis. For this reason, it’s crucial to understand your dog’s tolerance to high-fat food and evaluate the potential risks before jumping on this dietary regimen because the consequences could be severe.

This isn’t meant to discourage you but rather to emphasise informed decisions. Every dog is unique. Before making any dietary changes, consult a veterinarian or qualified dog nutritionist.

Fish Oil/Omega-3 Fatty Acids

Fish oil supplements that are rich in omega-3 fatty acids like EPA and DHA have been found to be very beneficial in cancer treatment. They can help reduce inflammation, slow down tumour growth, and improve quality of life. Opt for fish body oil instead of cod liver oil, which contain high levels of vitamin D and A.

For more information about choosing the best fish oil for your dog, click the following link: How to choose the best fish oil for your dog

Flaxseed oil

You might have seen flaxseed oil being promoted as an alternative to fish oil. This is because flaxseed oil contains ALA (alpha-linolenic acid), an omega-3 fatty acid. However, there’s a catch! The problem is that for a dog’s body to use it, ALA must be converted into EPA and DHA. These are the omega-3s that are present in fish oil. Unfortunately, the dog’s body doesn’t do this conversion very efficiently. As a result, only a tiny amount of flaxseed oil has omega-3 effects.

That said, flaxseed oil can be great for adding calories to your dog’s diet. However, if you want to add omega-3s, choose fish body oil over flaxseed oil.


Supplementing antioxidants during cancer treatment in dogs is controversial. Even veterinarians have conflicting opinions. Yet, most oncologists agree that antioxidants should only be supplemented within the daily nutritional needs established by the NRC.

The concern is that high doses of antioxidants may decrease the effectiveness of chemotherapy and radiation, potentially compromising or delaying your dog’s recovery.

Either way, there is no evidence to suggest that antioxidant-rich foods should be avoided during cancer therapy. In fact, it’s widely agreed that the amount of antioxidants found in whole foods is unlikely to interfere with treatment.

Antioxidants can primarily be found in vegetables and fruits. The bright and vibrant colours in fruits and vegetables usually indicate the presence of antioxidants. Therefore, the more colourful the food, the more likely it is to be rich in antioxidants. For instance:

  • Green of broccoli, kale, green beans and spinach
  • Red of cranberries, raspberries, pomegranates and ripe tomatoes
  • Orange of carrots and sweet potatoes
  • Yellow of mangos, squash and banana
  • Blue-purple of blueberries, blackberries and red cabbage.

If you’d like more information, as well as tips and tricks on incorporating fruits and vegetables into your dog’s diet, I suggest you go to the following blog post: Boost your dog’s health with fruits & vegetables

Digestive enzymes

Cancer can significantly affect the body’s capability to process and absorb nutrients from food. Digestive enzymes play a crucial role in breaking down food and enhancing nutrient absorption. Therefore, they can be highly beneficial, particularly for dogs who experience digestive issues due to illness or therapy

Different brands have different enzymatic effects, so talk to your oncologist or dog nutritionist to determine the best brand for your dog.


Having beneficial and friendly bacteria in the gut is essential to maintain optimal health and immunity.

Cancer treatment can disrupt this delicate bacterial balance, resulting in digestive problems. Therefore, introducing a probiotic supplement can help improve gut health

It’s important to keep in mind that not all probiotic brands are the same. Some brands may not actually provide the amount of probiotics that they claim on their labels. As with any supplement, quality is vital.

I usually recommend VSL#3 as the preferred probiotic for most dogs. The ideal dosage may vary depending on your dog’s weight. As a general guideline, I suggest using ½ sachet for every 10kg of your dog’s body weight. You can adjust the dosage as necessary.

Start with half the recommended dose for 3-4 days, then increase to full dose to allow your dog’s gut to adapt to the bacteria.

Reduced appetite

It’s not uncommon for dogs diagnosed with cancer to have a change in their appetite, which can lead to a decrease in their food and water intake.

Watching your dog turn away from their meals can be very distressing. Although there is no single solution that fits all, here are some tips and tricks that can help encourage your dog to eat when they are feeling unwell: How to get an ill dog to eat: Tips & tricks

And finally…

The journey with a dog diagnosed with cancer can be challenging. However, by focusing on proper nutrition, you can maximise your dog’s strength and overall health. Dogs with higher nutritional status are more likely to fight off infections, tolerate treatment and its side effects, and have better odds of winning the battle.

Team up with a dog nutritionist. They can create a tailored diet plan that takes into account your dog’s specific type of cancer, stage of the diease, and other health conditions while ensuring all essential nutrients are met.

At last, we’ve reached the end of the blog. I hope the information provided has helped you understand the essential changes needed to manage symptoms, treatments, and care for your dog. If you have any questions or need personal advice, please don’t hesitate to contact me at Your feedback and suggestions are always appreciated.

For more information on cancer in dogs, please check out the articles that I have written in the ‘Cancer Blog Section.

We’re here to help

If your dog has been diagnosed with cancer, we understand the challenges you face. For a consultation, please email us or learn more via the link below. We’ll be happy to help in any way that we can.

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