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How to Help a Cat with Kidney Disease Gain Weight

How to Help a Cat with Kidney Disease Gain Weight

Our cat, Olaf, who we have been managing his kidney disease for the last two years has had weight issues since his diagnosis. One of the things that tipped us to something being wrong is that he first started losing weight. This is what triggered us to learned all the ways to help our cat with Kidney Disease gain weight.

Since we now know this is a marker for things aren’t right we have started recording his weight at home. When we catch his numbers started to slide this is when we make sure to out a focus on his kCal intake as well as ways to supplement up some extra fat into his meals. We also know this is the time to go in and get a new set of lab work done to check his values. As we will touch upon later it’s always been to get to the root of why your cat isn’t feel like eating.

Calorie Boosting Gel

Okay I admit while it’s at the top of this list, it’s one of my last resorts. These calorie boosting gels are full of chemicals and identifiable ingredients. If you are here though I am sure it’s time to go the route of whatever it takes and these gels if your cat likes them do help. My cat is a junk food nut, he can’t help but go nuts for temptation treats so this aligned perfectly with his palette.

Personally after some research I went with the GNC Pets Ultra Mega High Calorie Booster Gel for Pets. Overall this item had better reviews than others on the market and I have used the brand before and trust them. It has some vitamins packed in and is even safe for use with kittens.

Duck Fat

This is my first go to when we are working on weight gain with my boy, Olaf. One of his favorite cat foods has duck in it so I knew as soon as I saw this suggestion that I had to give it a go. Duck fat is actually something that you can find at the grocery store.

I however opted to take the easy way out and just ordered a jar from Amazon that conveniently showed up the next day. Just make sure that there is no added salt, just pure duck fat.

Unsalted Butter

Can’t go wrong with fatten someone up with fat am I wrong? Butter is often very attractive to cats. Some people even use butter to coat pills they have to give their cats. There is one key piece here though, UNSALTED, make sure that you do not use salted butter. Also avoid any magazine or butter alternatives stick to the real deal, unsalted butter.

Eat Higher kCal Food

So the general rule of thumb is that the average indoor cat should have 20 calories per pound to maintain weight.  The average outdoor only cat should have 35 calories per pound to maintain weight. If you are looking to increase weight you would want to feed the calories of the ideal weight for your cat. This would most likely be their weight before they got sick. To be sure what the target is consult with your veterinarian. Our outlined everything for Olaf and gave us exact numbers (200 kcal/day) to get him back in the right range.

If you want to know how many calories you are giving your cat look at the back of the cat food where the nutritional information is listed. Here you are looking for somewhere that says the amount of kCals per serving. Since our cat is constantly rotating through a variety of flavors of food that all have varying kCal amounts I keep a running list so I can figure out his calorie intake per day.

Treat Topper

Sometimes cats just need that little extra incentive to eat when they aren’t feeling the greatest. Think of it like when you have a sore throat and you just want a bowl of ice cream. If our boy is suddenly deciding to turn his nose up at something he was just eating no issue a day or two before I will break out some treats.

Sometimes this means crushing up a temptation or two and sprinkling it on top. So far this has done the trick but I like to not do too often so he doesn’t expect it at every meal. If you want some more treat ideas read our best treats for cats with kidney disease.

Watch the Weight

When on a mission to get your cat’s weight back up the best way I find is to track everything. Watch the amount of food they eat, and get an idea of how many kCals they are eating in a day. This will show you what is working and what is not.

We also have the ability to easily weigh our cat at home and so can you! Here is our guide and FREE printable for tracking your cats weight at home.

Get to the Underlying Cause

If your cat is losing weight where they had been previously maintaining it’s time to head to the vet and get your kitty checked out. It could be harmless but odds are something is up and until you treat your ailment you could be fighting a losing battle.

For example our stage four CKD girl she developed mouth sore unknown to use at first. But it triggered to stop eating everything except our fridge cold raw and even that was declining in appeal. It was like her smell was getting worse and then we brought her into the vet. They first were only seeing signs of gingivitis (red inflamed gums) but then a couple days later when the nausea meds didn’t work our main vet was like look in her mouth I bet you will find open sores and boy did we ever, AWEFUL blisters, made me feel pretty bad I had missed this.

To give you a happier ending we did get it cleared up with a lot of patience and quite the medicine cocktail. She got a low dose of pain meds from the vet. Then I had whipped up my slippery elm bark paste to coat the open sores (super fun applying this as you can imagine) and lastly a consistent does of Pepcid AC. The Pepcid was due to the vet suspecting a possible acid reflux like issue where it was burning her throat and mouth we won’t get into all the yucky details of this.

Conclusion on Helping Your Cat with Kidney Disease Gain Weight

The key is to stick with it and not to give up. Can’t are finicky especially when they are not feeling well, so hang in there! If you are looking for ways to just get your cat to eat again try reading our tips here. If you have a trick to help your cat with kidney disease gain weight that you want to share with us be sure to let us know in the comments below!


Wednesday 13th of December 2023

My cat has been losing weight drastically. Shes stage 2 ckd and she weighs 6 pounds. Shes skin and bones. It saddens me. She also has hyperthyroidism. Barely but idk what to do to fatten her up. Shes on nausea meds i just started yesterday. I need to put more meat on her frail body. :( please help

Robin Griffin

Wednesday 13th of December 2023

You have to find food she will eat start with finding that, you can then add in fat (like duck fat they sell at grocery store) once you find food to get the calories up even higher. Tracking kcals is very helpful to know if you are hitting bench marks 200kcals per day should put her on track to gain to 7 pounds. You can even order a baby scale off amazon to track weight progress.


Saturday 15th of July 2023

My cat has lost weight. She just makes me so sad. I understand the kidney problem, I went through kidney failure and a transplant. Phyllis eats huge amounts of food, drinks lots of water and pees to the correct proportion. If she eats large kibble she does throw it up. She has been on begging stage kidney food. I’m taking her to the vet again to see what she suggests. This article provided me with some good ideas to try and fatten my girl up. Her energy levels are crazy and she thinks she is queen of the house. These are all good signs. Thank You

Robin Griffin

Saturday 15th of July 2023

If she is eating a lot of food and still losing weight definitely want to get a check up and make sure everything is good with the thyroid.


Monday 12th of December 2022

Hi, just reading your blog about cats with kidney disease. My Galipet also has this. We don't have dairy butter in the house but we used plant-based butters. Would these be OK, if they were salt-free? She seems desperate for it if she sees me having a bread n' butter treat. I don't want to deny her this pleasure but obviously not if it's bad for her kidneys. Thanks for any insight you have on this!

Robin Griffin

Monday 12th of December 2022

I would stick with real dairy based butter or even better some duck fat that's what I know the vet signed off on for us. Cat's are meat eaters and built to handle breaking down animals not so much on the veggies. But I always recommend running everything by your own cat's vet.


Monday 7th of March 2022

Thank you for the tips. My beloved Louis was diagnosed with CKD last year and we've been managing it pretty well, and even managed to get him to stage II from stage III, but his last appointment showed a decline and he's back in stage III. :( Among other concerns, his weight is down more. I was wondering how you served the duck fat? straight out of the jar? melted? with other food? thanks in advance for any further info you can provide.

Robin Griffin

Monday 7th of March 2022

Sometimes I would treat it straight out of the jar, like 1/8 teaspoon right on a spoon. He LOVED to eat off spoons if we served him. Sometimes we would also mix into his wet food. I would be cautious with melting and getting too hot. I also would not free feed out of a jar you want to limit. Too much fat all at once could cause an upset tummy which of course with kidney disease is the last thing we want.


Thursday 27th of January 2022

Temptations are horrible for cats. It triggered my cats renal disease. They make cates aggressive. My Vet does not recommend them.

I will try the duck fat & unsalted butter. Thank you!


Wednesday 14th of September 2022

@Carm, you gotta wonder whats in the temptations