Any tips for putting weight on CKD cat?

My oldest cat (14 years) has early stage kidney disease. Other than peeing a lot, he seems to feel well. He eats normally, grooms himself, is sociable, and is appropriately active for his age. But he’s slowly losing weight, and this worries me. He won’t eat any prescription diet, but I’m feeding him low phosphorous non-prescription Science Diet canned and dry food that he seems to like. I’m also supplementing him with vitamin B12. He loves butter, so I give him probably a tablespoon of that every day for the calories. Is there anything else I can do to put weight on him?

Also, he’s been tested for diabetes and hyperthyroidism, and those results were well within the reference ranges.

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Kidney disease can cause stomach ulcers, and also nausea. Pepcid is useful for ulcers, and a regular anti emetic helps with the nausea. My preference is zofran, but vets usually prescribe cerenia.

Vets are often reluctant to medicate for these issues, and you may have to insist. Pepcid is OTC, so at least that one is easy.


Have you tried different brands of food, Rx and non Rx?

Both my cats have renal disease, the old man, Sammy, is 17 and he’s lost weight with it. He does better when he eats the renal food but sometimes he decides it just won’t do and gets fancy feast. He eats the ff better but doesn’t hold weight on it.

I tried Purina and Hills renal diets but they both said no. They do like the Royal Canin renal support.

If yours won’t eat any of them I’d do some googling and find the highest calorie low phosphorus food I could find and try it. There is a list of low phosphorus foods at cat food info and Tanya’s crf websites.

My kidney cat is not a picky eater, other than he refuses to eat the prescription food. He eats the Science Diet low phosphorous food and finishes the leftovers the other two cats leave. He also supplements his diet with the occasional mouse. I read somewhere (don’t remember where, but it might have been Tanya’s chronic renal failure site) that these cats don’t absorb vitamin B12 well and they don’t digest fat well. I think that may be what’s going on with my cat, because he eats enough that he should be holding his weight. That’s why I started giving him B12 mixed in with his food and butter for a snack. He may be craving the butter because his body knows it needs the extra calories. But I wonder if there’s anything else I can do to get more calories into him without further damaging his kidneys.

Diabetes and hyperthyroidism both can cause weight loss despite a good appetite, but those have been ruled out. He could have cancer somewhere and that would be bad news. Bottom line is he’s getting old like we all do and I’ll lose him sooner than I would like. But I want to give him the best life I can until that day.


Right. You can do that by getting him to eat more, by treating the gastric ulcers and nausea that CKD causes. An appetite stimulant, like mirtazipine, can also be useful here…but making them hungrier before treating their nausea is kind of cruel, so treat the nausea first.


Can you try a different prescription food (not sure if you have) and see if he likes them better? You can do an Rx via Chewy if your vet only carries SD. The vet just has to fax it in, and then you can order it online.

Are you doing subQ’s yet? If not, I wonder if his weight loss is maybe related to losing fluids?

I’m not a huge fan of the prescription diets as they are very low in protein – to the point where the vet said my other cats shouldn’t eat it. Cats with compromised kidneys should be on low phosphorous diets. My kidney compromised cat did very well on Stella & Chewy Freeze dried chicken (rehydrated with lots of water). His bloodwork improved dramatically. I have a cat now that is in the early stages of kidney disease. I feed him that and also Weruva’s TruLuxe Cat Food, Steak Frites with Beef & Pumpkin in Gravy. That was one of the foods recommended by one of the websites. The bottom line is you need to find a food that your cat will eat and sometimes that takes a lot of experimentation.


Can you talk to your vet about a half-and-half diet? (Half Rx and half higher calorie OTC, maybe with a phosphorus binder?)

Echoing the appetite stimulant suggestion. Also, some of the probiotic powders are cat crack and make even meh foods tasty when mixed in.

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I think I haven’t been clear with my explanation of what’s going on with my cat. The problem isn’t that he doesn’t eat or that he’s nauseated. On the contrary, he does eat, and he eats at least as much as my other cats. The problem seems to be that his digestive system isn’t absorbing all those calories. He craves butter, and that makes me think he needs more fat.

@Alex_and_Bodie_s_Mom, I’m not doing sub-Qs yet. He drinks enough to compensate for the increased urine and is not dehydrated. (And in a big digression from the topic at hand–way to go Kansas!)

@Simkie, I’m not seeing any signs of nausea–no vomiting, no lip licking, no reluctance to eat. But yes, when he starts showing signs of nausea I’ll definitely treat it.

@Bogie, I haven’t tried the foods you mentioned, but now they are on my list of things to try. I’m looking for foods or supplements with higher fat/calorie content but low phosphorous.

@BootsAndCoffee I’ve tried mixing the prescription food with some low phosphorous non-prescription food. He just picked out all the yummy non-prescription food and left the rest for the dog. I’ve also tried all the prescription foods but no luck there either.

I have had 4 CKD cats, all young (sadly) in the last 6 or so years, including my current 4 and 5 year olds. Internist thinks God sends them to me (if so, can you please lay off, God?). I think it’s because I live in an industrial wasteland and my cats (and rescues) are all street kitties.

I highly recommend Tanya CKD (aka - the list-serve, website and lastly the book.

FAIR WARNING: There is a lot of moderation (more-so since I left) and some unnecessary drama/politics, but there are a lot of really excellent, lovely people who can give you great advice. Some of them I consider life long friends - whether I have met in person with them or not. They really got me through the hell that was my first CKD experience (heart cat died a year to the day from diagnosis… but from comorbidities, not from CKD - she had a LOT going on). Join now when you aren’t in crisis - there is a waiting period while the mods approve that is excruciating if you are in crisis, as I was when I first found it. Regardless of caveats, it’s a great resource.

I have been off the board for years now (subscribe but don’t participate), but there are a lot of non-Rx foods that are lower Phosphorus that either Helen’s lists (see below) or users can steer you towards.

Mine currently eat Rx just fine (even though younger cat is tiny and not a great eater and it makes me nervous, my vets aren’t concerned yet), but I used Helen’s lists a LOT in the past. She updated them periodically:

Feel free to PM!

Also, my cats are going on 2 years now post Dx and are amazing. Previous cat was adopted out and also doing great! So 3 out of 4 after several years! CKD sucks, but it’s more manageable than people imagine.



Having gone through this (sadly) several times, if he were eating enough, he would not be thin. To get to not thin, he needs more calories. Getting him to eat more is, ime, the best way to accomplish that.

Cats are massively stoic little creatures. Chronic renal failure causes nausea and ulcers. That you think you’re not seeing any signs doesn’t really matter–the disease causes nausea.

Treating the nausea & using an appetite stimulant not only addresses the issue of him being thin, but improves quality of life in a really massive way. By the time they’re showing the really obvious symptoms of nausea that you describe, they’re really suffering.

It could be that he’s not getting enough quality protein, I like the foods Bogie mentioned. Too much butter can possibly result in pancreatitis so I would be careful with that. It’s tough with the CKD kitties in that the recommendation is to limit protein but if they don’t get enough good quality protein, muscle wasting will occur. They are obligate carnivores.

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Yeah, really good catch there. Pancreatitis is such a bear. Definitely don’t need to be adding that :grimacing:

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My vet encouraged me to find a group to join to help with nutrition for my old man with kidney disease (he’s an Erin cat :smiley_cat:). I found the Feline Chronic Kidney Disease group on Facebook and they have been wonderful. One of the members is a whiz at keeping lists of which foods are safe and is happy to give advice based on your cat’s individual lab results.
As you move into giving fluids etc people give great advice on what tricks have worked for them. It’s been really helpful.


One more suggestion. I haven’t seen these foods mentioned with CKD cats, but I have a special snowflake right now who had massive digestive issues including explosive diarrhea. I could not get him to hold weight. I tried any number of foods and my vet recommended trying pumpkin as a way of soothing his intestinal tract. Of course, my special cat won’t eat pumpkin puree but he LOVES the R&D canned and dried foods with added pumpkin. No more digestive upset, no more diarrhea, no more inflamed intestinal tract. Slightly less expensive than prescription food. For him it’s been a life saver as my vet told me with chronic inflammation like he showed, he’d likely get cancer. Said cat was a rescue who lived on the streets for some time, so I have to wonder if a very poor diet created the problem.

My older cat is doing quite well with frequent feedings, and a variety of high-quality wet foods. Currently she is eating Fancy Feast pate, but I expect she will refuse it soon. When that happens we try Cat Person, Koha or Blue Wilderness. She does better with small feedings every two hours or so, which can be inconvenient, but she’s family.

Yes I know. That’s why I’m looking for better options!