Hello from Greycoat Research,

This is Alex Shin.

Today, I would like to share a practical nutrition note for guardians caring for cats with advanced CKD, especially stage 3 or later.

At Greycoat Research, we have guided more than 4,500 kidney care consultations for cats. Through these cases, we have learned that cats with stage 3 or later CKD often need a more careful nutritional approach, not just general kidney support.

This article is not a medical prescription. It is a personal care note based on what I have learned while supporting many cats with chronic kidney disease.

What We Watch Closely in Stage 3 or Later CKD

In cats with stage 3 or later CKD, we pay close attention to several major concerns: metabolic acidosis, anemia, electrolyte imbalance, and uremic burden.

Among these, one of the most practical things guardians can watch is whether BUN is rising too quickly.

BUN is closely related to nitrogen waste produced from protein metabolism.

When kidney function declines, the body may have more difficulty clearing these waste products.

As BUN rises, the uremic burden may also increase. Of course, uremia cannot be judged by BUN alone. A cat’s overall condition, creatinine, phosphorus, electrolytes, appetite, hydration, body weight, and clinical signs all matter.

However, in cats with advanced CKD, BUN is still one of the important markers we watch when thinking about uremic burden.

This is why, when BUN continues to rise, reducing protein burden while maintaining enough calories becomes very important.

The Key Is Not Simply Feeding Less

Because BUN is related to protein metabolism, reducing protein burden may help in some cats with advanced CKD.

In cats with high BUN or signs that suggest uremic burden, a very low-protein nutritional approach may sometimes be considered.

But the important point is this: feeding less is not the same as managing CKD well.

If we simply reduce food, protein intake may go down — but calories will also go down.

When calories are not enough, a cat may start breaking down its own muscle for energy. This can lead to weight loss, muscle loss, weakness, and a worse overall condition.

So for cats with stage 3 or later CKD, the goal is not just to reduce protein.

The goal is to reduce unnecessary protein burden while protecting calorie intake, body weight, and muscle.

This balance is difficult, but it is one of the most important points in advanced CKD nutrition.

Royal Canin Renal Liquid Can Be a Practical Assisted-Feeding Option

One practical option I often consider in this situation is Royal Canin Renal Liquid.

This is not a Greycoat Research product. However, from a nutritional care perspective,
I believe it can be helpful for some cats with mid-to-late stage CKD.

It is important to understand that Royal Canin Renal Liquid is not just a regular food topper.

It should be understood as a liquid renal diet for cats that need assisted feeding, such as syringe feeding or tube feeding, especially when they cannot eat enough on their own.

In other words, this is not something I see as a casual food topper.

For this reason, I consider it most useful when a CKD cat needs calorie support but cannot maintain enough intake through regular renal food alone.

This type of liquid renal diet can provide calories in a smaller feeding volume while keeping the formula designed for renal support.

For cats with high BUN, poor appetite, or difficulty maintaining body weight,
this can be a very practical option.

Because this product is often used for assisted feeding, guardians should discuss the best feeding method with their veterinarian.

If Renal Liquid Is Not Available, C8 MCT Oil Powder May Be Considered

However, not every guardian can easily access Royal Canin Renal Liquid.

In those cases, one approach I personally consider is reducing the amount of renal wet food slightly, while adding calories through MCT oil powder.

In particular, C8-based MCT oil powder may be useful because it can be converted into energy relatively quickly.

C8 MCT is absorbed and metabolized differently from many long-chain fats, and it may provide a rapid source of calories without increasing protein intake.

In other words, it may help provide extra calories while keeping protein burden lower.

This can be useful when we want to protect body weight and muscle without increasing the protein load that may contribute to rising BUN.

When choosing an MCT oil powder, I prefer a product with minimal added sugar or unnecessary carbohydrates.

Not all MCT oil powders are the same. Some powders may contain added sugars, starches, sweeteners, flavors, or carbohydrate-based carriers, so the ingredient list should be checked carefully.

I Do Not Recommend Raising Calories with Sugar

When a cat needs more calories, I do not recommend using sugar, syrup, honey, or sugary treats to increase calorie intake.

Sugar may provide quick energy, but for cats with advanced CKD, this is not an ideal approach.

A sugar-based calorie strategy may increase blood sugar burden and unnecessary metabolic stress.

For a cat whose body is already working hard to manage waste products, electrolytes, hydration, and acid-base balance, simply adding sugar for calories can be risky.

This is why I do not use sugar to increase calories in CKD cats.

If calories need to be supported, I prefer an approach that does not increase protein burden and does not rely on sugar.

For this reason, C8-based MCT oil powder can be a more practical option in selected cats.

There Are Two Practical Ways to Give MCT Oil Powder

There are two ways guardians may consider using MCT oil powder.

The first way is to mix a very small amount of MCT oil powder into renal wet food.

The second way is to place MCT oil powder into a capsule and give it separately from food.

However, I do not recommend mixing it into the cat’s entire main meal at the beginning.

Some cats may dislike the taste or smell of MCT oil powder, especially C8-based products. If the cat begins to avoid the food, the strategy can backfire.

So if the cat is already eating only a small amount, it may be safer to test it separately first, rather than mixing it into the only food the cat accepts.

The core idea is simple.

If we increase the amount of renal food too much, protein intake may also increase.

But if we reduce renal food too much, calories may become insufficient.

So the strategy is to reduce unnecessary protein burden while replacing some of the missing calories with MCT oil powder.

For some cats, this may be a practical way to help defend against further BUN increase while protecting body weight and muscle.

Liver, Pancreas, and Appetite Must Be Considered

MCTs are metabolized quickly, mainly through the liver.

For this reason, I do not recommend this approach for cats with liver problems, abnormal liver values, or suspected liver disease.

Cats with pancreatic issues or sensitivity to fat intake also need extra caution.

It is also important to remember that some cats may not like the taste or smell of MCT oil powder, especially C8-based products.

If appetite drops, stool becomes loose, vomiting occurs, or the cat shows discomfort, this approach should be stopped or adjusted.

Start with a very small amount and watch carefully.

This approach should be considered together with the cat’s liver values, pancreatic condition, body weight, appetite, stool condition, hydration, and overall bloodwork.

The Main Point: Balance Protein Burden and Calories

For cats with stage 3 or later CKD, BUN management is not only about reducing protein.

It is about reducing unnecessary protein burden while still protecting calories, body weight, and muscle.

Royal Canin Renal Liquid can be a practical assisted-feeding option for this purpose.

If it is not available, a combination of renal wet food and C8-based MCT oil powder may be considered as a practical alternative for selected cats.

The key is simple:

reduce protein burden carefully,
avoid sugar-based calorie strategies,
and protect the cat from calorie deficiency and muscle loss.

This is one of the nutritional strategies I personally consider when supporting cats with advanced CKD and rising BUN.

Again, this is not a medical prescription. It is a practical nutrition note based on my personal care experience with many cats with kidney disease.

Every cat is different.

Please consider your cat’s bloodwork, body weight, appetite, liver values, pancreatic condition, anemia status, hydration, and overall condition before applying this approach.

Greycoat Research