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Written by leading veterinarians to provide you with the information you need to care for your pets.

Nutrition Nuggets is the newest offshoot of petMD's Cat Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of cat nutrition.

Cats with Cancer – What should they Eat?

July 10, 2015 / (2) comments

Taking care of a cat with cancer is hard enough, but when his or her appetite begins to wane, questions about quality of life soon follow. Watching a sick cat’s food intake is very important for two reasons:


  1. Cats will often lose their appetite when they don’t feel well, so food intake can be used as a quality of life indicator.
  1. Good nutrition is never more important than when a cat is battling cancer.


The first step in improving a cancer patient’s appetite is to try to identify anything “fixable” that might be adversely affecting a cat’s willingness or ability to eat. Is the cat on any medication that could be depressing her appetite? Is discontinuing it or switching to another drug possible? Are there palliative treatment options (pain relief, surgery, radiation therapy) that could improve the cat’s appetite even if they aren’t expected to be curative? Is a feeding tube a reasonable choice?


The next question that arises is, “What’s the optimal diet for a feline cancer patient?” Cancerous cells alter the body’s metabolism. They metabolize glucose and make lactate that the body then tries to convert back into glucose. This takes energy away from the cat and gives it to the cancer. Cancers also convert amino acids, the building blocks of protein, into energy, causing muscle wasting, poor immune function, and slow healing. On the other hand, cancerous cells do not appear to be very efficient at using fat as an energy source.


Based on these metabolic changes, many veterinarians recommend feeding feline cancer patients diets that are relatively low in carbohydrates (particularly simple carbohydrates), and high in protein and fat. It is important that all the ingredients used to make the cat’s food be highly digestible and absorbable. Just enough fiber should be included to maintain normal bowel function without significantly “diluting” the food. Omega-3 fatty acids are often added to these diets because they are a good source of fat and calories and may have “anti-cancer” effects.


In all honesty, there hasn’t been a lot of research into whether or not these types of diets actually improve outcomes in cats. The study that is most often cited was done in dogs with lymphoma, and while the results were positive, who’s to say that a similar diet would have the same effect with a different type of cancer and/or in a different species? I don’t worry too much about this, though, since a diet that is low in carbs and high in protein and fat is appropriate for any cat that is eating poorly and at risk for the adverse effects of unwanted weight loss.


Commercially prepared foods are widely available that fit these parameters. Canned varieties are best, but dry is an option if that is what a cat prefers (now is not the time to force a diet change!). Veterinary nutritionists can also design recipes for home prepared foods that meet the special needs of feline cancer patients.



Dr. Jennifer Coates



Image: Natata / Shutterstock


Comments  2

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  • Cancer Kitties
    07/31/2015 09:03pm

    I currently have two cancer kitties. Although both appear to be in remission, I'm a firm believer in letting them have whatever they want. Owen is happily getting a massive amount of treats and Josie (she's always been very picky), well, we try multiple things every day.

    It's a quality of life thing.

  • Cat mascell tumor cancer
    10/23/2015 12:09am

    My 11 year old precious kitty Peyton had a lifetime of herpes like symptoms that req. repeat antibiodic use & lysine, along with an anti-histamine. Then at age 10 (the most common age for MSTC) he developed a large tumor on his rear end. I had that removed; told it was non-cancerous & not to worry. The best thing that happened in the meantime was finding our current family vet, who helped find even more on his neck area and flanks. After seeing this was running rampant, she graciously sent us to a pet oncologist, where he has been undergoing chemo for this. Ironically, the frequent herpes attacks vanished. I would love to know the correlation between the two. So far, so good. I have made the point to learn any & all nutrition needed for my cats, esp. when having cancer. I supplement with the krill oil (they will not touch fish oil!) the spirugreen nutritional for pets only algae filled with rich nutrition from a pure source, pre and pro-biodics, grain free moist food which I mix these items in and if I can also add the Cosequin powder for bone health as the chemo does attack bones. Lysine gel/powder is a must for a boosted immune system. Special attention needs to be paid to their teeth/gums; Peyton had 3 teeth just drop out, and he will occas. develop a chemo blister on the gum. Despite this, he has still developed a gastric issue, along with a "bloat" type of reaction to his small frame. Normally 10 pounds, he is swollen up to 19, & the only food he can now eat without severe diarrhea is the Satiety low cal by Royal Canin. He never had a sensitive stomach prior to this, so it is a very touchy subject as far as getting the nutrients to stay in him without dehydration. I also will poach in pure water non GMO, antibiodic free chicken breast strips and serve them to him as a treat; providing protein without the extra fat. He loves it and eats it all up. At first chemo treatment a over a year ago now, he did lose his coat about the neck & shoulder area, now with this added nutrition, oils, and organic vitamins I also add to all of his food, his coat is thicker than ever before. Eyes clear and bright and he is actually the alpha cat yet in the house of four now. We have tried the Glyco Balance diet in the hope of getting the weight down on him however it made him extremely sick so it is back to what works; the Satiety diet. In today's world, we have excellent access to very affordable pet nutrition; and in the case of any type of cancer I feel it is mandatory to supplement the pet's diet with any and all nutritional vitamins, minerals, oils, bone, urinary health natural treats to give them the very best chance at a recovery. Thank you for this article. Terri D, Peyton's mom.