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 you’re interested in a consultation, please email us or learn more via the link below. We’ll be happy to help in any way that we can.

Updated October 2023, by Kristina Johansen Cert. ACN

In this guide to diet for dogs with cancer, our primary focus will be on food. However, we will also delve into various relevant topics such as:

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

Let’s dive in!

My dog has cancer, what now?

No one wants to be given the news that their dog has cancer. But if you find yourself in this position, 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 medical treatments should be managed by both a qualified oncologist and your veterinarian, you can improve 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 better tolerate treatment and its side effects.

Good nutrition can also help your dog maintain a healthy weight and prevent or reduce the effects of cachexia, a condition characterized by muscle wasting commonly associated with cancer treatment.

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, here are some key guidelines to consider when planning your dog’s diet during their cancer battle.

Calories & nutrient content

Making sure that 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 is dealing with cancer, one of the first things you might notice is weight loss. This is because the disease itself, along with side effect of chemotherapy and radiotherapy, may cause rapid muscle wasting and loss of appetite.

The good news? The right kind of food can make a significant difference.

The goal here is to offer foods your dog favours, 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 good calorie and nutrient-dense food options that most dogs favour include:

  • Eggs
  • Mackerel
  • Ricotta cheese
  • Lamb
  • Beef

High-quality protein

Dogs battling cancer typically require more protein than usual. This is because protein plays a vital role in growth and repair. Without enough protein, it can take longer for your dog’s body to recover from illnesses, especially after cancer treatments like chemotherapy and radiotherapy.

However, it’s not just about the quantity of proteins. Quality also plays a critical role in the diet for dogs with cancer.

Not all protein offers the same nutritional value, digestibility, or benefits. That’s why it’s essential to consider something called the Biological Value (BV) of a protein source when choosing the best protein for dogs with cancer.

Biological Value measures how efficiently your dog’s body uses that protein. Proteins with higher biological values are better absorbed and used by the body, making them the go-to choice.

Good sources of high-quality protein for dogs with cancer 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 made the villain of ‘cancer’ diets. You may have heard that they feed cancer cells and help them grow. However, the relationship between cancer cells and carbohydrates is actually quite complex.

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.

I’m not recommending a high-carbohydrate diet for dogs with cancer by any means. You need to consider what is best for your dog’s individual needs. 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).

Additionally, many carbohydrates are rich in antioxidants, that can help protect cells from damage. So, they’re not all bad news.

Here are some high-calorie carbohydrate choices:

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

And here are some low-calorie options:

  • Broccoli
  • Blueberries
  • Apple
  • Carrots
  • Bell peppers


Fats play a crucial role in a diet for dogs with cancer. They not only increase the calorie content of the meal but also enhance its palatability. This is particularly vital for dogs whose appetite may be affected by the disease.

Good sources of added fats and foods that naturally contain a higher proportion of fat for dogs with cancer include:

  • Olive oil
  • Coconut oil
  • Flaxseed oil
  • Fish oil
  • Whole eggs
  • 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 a state called ketosis. In ketosis, the body primarily relies on ketones, derived from fats, for energy rather than carbohydrates (glucose).

I’m a visual person, so I made a little 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 glycose for energy. So, by changing the diet to a high-fat, low-carb diet, theoretically, the body will use fat as energy while cancer cells are starved.

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 in humans, and translating these findings to dogs is not straightforward.

What this means is that we need more studies to establish the long-term effectiveness and safety of ketogenic diets for dogs with cancer.

My two pennies worth

Before embarking on a keto diet, please consider this:

To reach a state of ketosis, a dog’s diet must consist of a high percentage of fat, often surpassing 70% of dry matter (DM). However, it’s essential to remember that this approach is not suitable for all 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 with a veterinarian or qualified dog nutritionist.

Fish Oil/Omega-3 Fatty Acids

Fish oil supplements rich in the omega 3 fatty acids EPA and DHA (the good stuff), play an important role in cancer treatment. They have shown to reduce inflammation, slow tumour growth, and improve quality of life. Opt for fish body oil and avoid cod liver oil, which is high in vitamin D and A.

For more information on fish oil, you can follow the link to ‘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. Flaxseed oil contains the omega-3 fatty acid ALA (alpha-linolenic acid). The problem with ALA is that for a dog’s body to use it, it must be converted into EPA and DHA – the omega-3s found in fish oil. Unfortunately, a dog’s body doesn’t do this conversion very efficiently. As a result, only a small fraction of flaxseed oil has omega-3 effects.

Flaxseed oil can be effective for adding calories to your dog’s diet. However, if you’re looking to add omega-3s and your dog tolerates fish body oil, choose that over flaxseed oil.


Antioxidant supplementation in dogs undergoing cancer treatment is a controversial subject. Even veterinarians have conflicting opinions. Yet, most oncologists seem to agree that antioxidants should not be supplemented beyond the daily nutritional needs established by the NRC.

The concern arises because high doses of antioxidants might reduce the effectiveness of chemotherapy and radiation, potentially compromising or even delaying your dog’s recovery.

Either way, there’s no evidence to suggest that antioxidant-rich, whole foods should be avoided during cancer therapy. It is believed that the level of any single antioxidant in a whole food is unlikely to interfere with treatment.

So, to safely introduce antioxidants to your dog’s diet, opt for antioxidant-rich foods like vegetables and fruits. Remember, each fruit and vegetable has its own unique composition, so feed a variety of colours.

For more information on adding vegetables and fruits to your dog’s diet, you can follow the link to ‘Boost your dog’s health with fruits & vegetables’.

Digestive enzymes

The body’s ability to process and absorb nutrients in the food can be greatly affected by cancer. Digestive enzymes help the body to break down food, making it easier to absorb nutrients. Thus, they can be extremely valuable, in particular for dogs who experience digestive problems due to their illness or treatment.

There are many brands out there with different enzymatic effects, so talk to your oncologist or dog nutritionist about the best brand for your dog.


Beneficial ‘friendly’ bacteria are essential for maintaining optimal gut health and immunity.

Unfortunately, cancer treatments, including chemotherapy and radiation, can disturb this delicate bacterial balance, resulting in digestive problems. Therefore, introducing a probiotic supplement can offer several health benefits.

It’s crucial to note that not all probiotic brands are created equal. Some do not deliver the probiotic quantities they claim on their labels, and others might even be contaminated with harmful organisms. As with any supplements, the quality is paramount.

I personally recommend VSL#3. It’s a very high-quality probiotic supplement. While the ideal dosage can differ between individual dogs, a general guideline is ½ sachet for every 10kg of body weight, adjusting as necessary.

Given its potency, I recommend starting with half the suggested dose for the initial 3 – 4 days. This allows your dog’s gut to adapt to the bacteria before increasing to the full dose.

Reduced appetite

It’s not uncommon for dogs with cancer to experience changes in their appetite, leading to decreased food and water intake.

Witnessing your dog turn away from their meals can be incredibly distressing. While there’s no one-size-fits-all solution, the following suggestions may help encourage your dog to eat: How to get a sick 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 a higher nutritional status are not only more likely to fight off infections and tolerate therapy and its side effects, but they also have better odds of actually winning the battle.

Team up with a dog nutritionist. They can provide a tailored diet plan that considers your dog’s specific type of cancer, its stage, and any 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 get in touch at I always appreciate your feedback and suggestions.

For a deeper understanding of cancer in dogs, you can explore the various articles I’ve written in our ‘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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