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  • Writer's pictureDr Becca Leung

Ketogenic dog food for cancer

Updated: Jun 6



Last month, our dog, Boston, was diagnosed with osteosarcoma, an aggressive form of bone cancer. We didn’t see it coming and were devastated by the news that she may only have a few months to a year to live. After a period of shock, my husband and I pulled ourselves up by our bootstraps and are doing everything we can for Boston to give her the best quality of life for as long as possible. This included the amputation of her front leg and a course of chemotherapy, which we’re undergoing. Also, her nutrition has never been as important as it is now. Because she now needs to learn how to move on three legs, maintaining a lean and strong physic is vital for her. My goal is to maintain her at a lean but strong 4 out of 9 body condition. I’ve also changed her diet to a ketogenic diet, and I wanted to share why I did that, and to caution why it might not be right for all dogs with cancer. 


A ketogenic diet is a high fat, moderate to low protein, very low carbohydrate diet that promotes something called "nutritional ketosis". A classic ketogenic diet for a person means they would be getting an impressive 90% of their daily calories from fat, 8% from protein and a tiny 2% from carbohydrates. This can be a hard diet for people to follow as it really limits what they can eat. Although we all know fat is tasty, too much of it can be sickly. There are modified versions of the classic ketogenic diet that is less strict as a result. When it comes to our pups, I’m concerned that the classic ketogenic diet is not appropriate for them. Humans have a lower protein requirement than dogs, and feeding a diet too low in protein will increase the risk of muscle loss, amongst other things. So, for Boston, she is getting a home-made diet which contains less fat and more protein compared to the classic ketogenic diet: about 65% of calories from fat, 30% calories from protein, and 5% calories from carrot and kale. This gives her over 1.5x’s her minimum protein requirement.

 

So, what does a ketogenic diet do? By basically eating very little to no carbohydrates, there is a change in the metabolism in the body - favouring fat oxidation. So in other words, the body switches from mainly using glucose from carbohydrates to fuel cells to ketones from fat. Why could changing from glucose to ketones to fuel the body make a difference with cancers? Well, due to their rapid proliferation, cancer cells need lots of glucose for energy using a particular pathway in the cell that doesn’t require oxygen. This quirk is present in over 80% of different types of cancer cells and is called the Warburg Effect (1). That means that these types of cells are reliant on glucose to spread and invade, which is what cancer cells do best. And the theory is, by reducing how much glucose is around in the body, you can affect how quickly cancer cells develop and proliferate.




What does the evidence say about this? Well, there are actually quite a lot of rodent studies with different cancer types which found that a ketogenic diet can delay tumour development and increase survival times (2). But it’s not all positive as other studies suggest that a ketogenic diet could actually accelerate tumour growth, like in rat models of kidney cancer (3). Also, another study showed that ketogenic diets can cause cachexia and actually shortens survival time (4). The researchers believed it was due to a suppression of corticosteroids as an effect of the ketogenic diet. What the overall take away from these studies is that it’s important that we don’t treat all cancers the same, and different types may react differently to a ketogenic diet. We also don’t have a full understanding of all the mechanisms yet as well, which is something important to keep in mind.

 

There are a few human trials which have looked at ketogenic diets on different types of cancers. The ketogenic diets are given with other forms of treatment – so surgery, chemotherapy, and radiation therapy. It’s never the sole treatment. Overall, these trials found that the diets are fairly well tolerated, didn’t cause major side effects, and were associated with improved outcomes and quality of life (5). Some reported minor side effects such as nausea, vomiting, cramping, and fatigue, so it’s not completely inert (5).

 

In dogs, there are only a handful of case studies of dogs with cancer on ketogenic diets, mostly published as abstracts and not full studies (6). A recent publication in 2023 involved a dog with a resolving mast cell tumour where the ketogenic diet was the only treatment given (7). They also fed to 60% of estimated energy requirement, so it was not only a ketogenic diet, but also a calorically restriction diet. While this case is really interesting, it is only one report. So, we need much more robust studies in veterinary medicine to really know whether it is helping, and to make sure it's not hurting.

 

In saying all of that, why did I still choose to put Boston on a ketogenic diet then? Well, dogs do not have a requirement for digestible carbohydrates, as they can produce the small amount of glucose needed in the body through protein metabolism. So, she doesn’t need it. And there are other potential benefits outside of reducing tumour growth where a high fat diet could be beneficial. One of the factors that has been shown to be associated with poorer prognoses in canine cancer patients is having low body weight at diagnosis or subsequent weight loss (8,9). A loss of body weight and muscling can lead to a loss of strength, mobility, and quality of life. By giving a high fat diet, the volume of food needed to be eaten is reduced, so that may help with maintaining body weight. In addition, fat is palatable to dogs, and they will actively choose a higher fat diet if given the choice (10,11). So that is another benefit of a high fat diet.

 

There are definitely some precautions to take though. Some dogs can develop pancreatitis if given a high fat diet, especially if it’s given suddenly (12,13). I’ve found that Boston doesn’t tolerate dietary change as well as she used to, which is something I’ve spoken about previously in the blog about how to transition a pet onto a new diet. So, I transitioned Boston very slowly, over 10 days, from her old diet to her new, ketogenic diet. It's also important that giving fat doesn’t come at the expense of giving protein. You will also need to consider bumping up the vitamin E content of the diet, especially if you're enriching the diet with polyunsaturated fatty acids (namely omega-3, EPA and DHA). Finally, I want to emphasize that there is no evidence that feeding a ketogenic diet can prevent cancer to begin with. Foods that provide digestible carbohydrates can be rich in other important nutrients such as fibres to support the microbiota and phytonutrients. So, in healthy dogs, leaving out the carbs can mean you’re also leaving out other nutrients that are also important for a healthy, balanced diet.

 

I hope that was a helpful summary of our current state of understanding of ketogenic diets and cancers. We’re going to continue closely monitoring Boston’s body weight and muscle condition to make sure that her ketogenic diet is suiting her, in addition to giving her all our love every day ❤️



  1. Vaupel, P., & Multhoff, G. (2021). Revisiting the Warburg effect: historical dogma versus current understanding. The Journal of physiology599(6), 1745-1757.

  2. Weber, D. D., Aminzadeh-Gohari, S., Tulipan, J., Catalano, L., Feichtinger, R. G., & Kofler, B. (2020). Ketogenic diet in the treatment of cancer–where do we stand?. Molecular metabolism33, 102-121.

  3. Liśkiewicz, A. D., Kasprowska, D., Wojakowska, A., Polański, K., Lewin–Kowalik, J., Kotulska, K., & Jędrzejowska–Szypułka, H. (2016). Long-term high fat ketogenic diet promotes renal tumor growth in a rat model of tuberous sclerosis. Scientific Reports6(1), 21807

  4. Ferrer, M., Mourikis, N., Davidson, E. E., Kleeman, S. O., Zaccaria, M., Habel, J., ... & Janowitz, T. (2023). Ketogenic diet promotes tumor ferroptosis but induces relative corticosterone deficiency that accelerates cachexia. Cell Metabolism35(7), 1147-1162.

  5. Lane, J., Brown, N. I., Williams, S., Plaisance, E. P., & Fontaine, K. R. (2021). Ketogenic diet for cancer: critical assessment and research recommendations. Nutrients13(10), 3562.

  6. Seyfried, T. N., Mukherjee, P., Lee, D. C., Ta, L., & Nations, L. (2023). Case report: Resolution of malignant canine mast cell tumor using ketogenic metabolic therapy alone. Frontiers in Nutrition10, 1157517.

  7. Vendramini, T. H., Amaral, A. R., Rentas, M. F., Nogueira, J. P. D. S., Pedrinelli, V., de Oliveira, V. V., ... & Brunetto, M. A. (2024). Ketogenic diets: A systematic review of current scientific evidence and possible applicability in dogs and cats. Journal of Animal Physiology and Animal Nutrition108(2), 541-556.

  8. Romano, F. R., Heinze, C. R., Barber, L. G., Mason, J. B., & Freeman, L. M. (2016). Association between body condition score and cancer prognosis in dogs with lymphoma and osteosarcoma. Journal of veterinary internal medicine30(4), 1179-1186.

  9. Lee, W. S., Lee, J. J., Liao, A. T., Kao, C. L., & Wang, S. L. (2021). Association between weight change during initial chemotherapy and clinical outcome in dogs with multicentric lymphoma. Veterinary and comparative oncology19(1), 53-60.

  10. Hewson-Hughes, A. K., Hewson-Hughes, V. L., Colyer, A., Miller, A. T., McGrane, S. J., Hall, S. R., ... & Raubenheimer, D. (2013). Geometric analysis of macronutrient selection in breeds of the domestic dog, Canis lupus familiaris. Behavioral ecology24(1), 293-304.

  11. Roberts, M. T., Bermingham, E. N., Cave, N. J., Young, W., McKenzie, C. M., & Thomas, D. G. (2018). Macronutrient intake of dogs, self‐selecting diets varying in composition offered ad libitum. Journal of animal physiology and animal nutrition102(2), 568-575.

  12. Lem, K. Y., Fosgate, G. T., Norby, B., & Steiner, J. M. (2008). Associations between dietary factors and pancreatitis in dogs. Journal of the American Veterinary Medical Association233(9), 1425-1431.

  13. Cridge, H., Lim, S. Y., Algül, H., & Steiner, J. M. (2022). New insights into the etiology, risk factors, and pathogenesis of pancreatitis in dogs: Potential impacts on clinical practice. Journal of Veterinary Internal Medicine36(3), 847-864.



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