Cats are obligate carnivores, which means they are built to eat meat, not the high-carbohydrate dry kibble most of us have been told is complete and balanced. The best diet for a cat is high in protein, high in moisture and low in carbohydrate. In practice, that means gently cooked food, good quality canned (wet) food, and appropriate raw meat, fed to suit your cat’s life stage. Here is why, and how to make the change safely.
Leonardo da Vinci once said that “the smallest feline is a masterpiece.” As a vet seeing cats day in and day out, I agree. Cats deserve to be seen and treated as the marvels they are, and that starts with what goes in the bowl. In our last article, we looked at why standard kibble falls short for our dogs and cats. This is the feline side of that story, based on the science, on what I have seen in practice, and on what I feed the cats in my own care.
Are cats really obligate carnivores?
Yes. A cat is an obligate carnivore, an animal whose body can only run properly on a meat-based diet. Cats are not small dogs. Dogs evolved into omnivores, so their bodies can handle higher levels of carbohydrate than their wolf ancestors could. Cats did not. Their anatomy and biochemistry are unyielding about what they can eat, and they are designed around highly digestible protein and fat, not starch.
For a long time, dry kibble has been sold as a convenient, complete and balanced diet for cats. Unfortunately, that claim rests more on convenience, marketing and cost than on nutritional science. A diet of ultra-processed, carbohydrate-heavy dry food is one of the drivers behind the modern rise in chronic feline illness. To understand why, it helps to look at how a cat is built.
Cats are not designed to digest carbohydrates
It starts in the mouth. A cat’s saliva only lubricates the throat to help swallow small prey like a mouse. It contains no salivary amylase, the enzyme that begins breaking down starch. Human and dog saliva both contain it, so we start digesting carbohydrates the moment we eat. Cats cannot. Further down, a cat produces only small amounts of the pancreatic and intestinal enzymes needed to digest carbohydrate, and the feline gut is short and acidic, built to handle bioavailable protein and fat.
In the wild, the only carbohydrate a cat eats is the tiny amount in the stomach of its prey. Yet dry kibble typically contains somewhere between 30 and 60 percent carbohydrate, because starch is needed as a binder to hold the biscuit together. Compare that with the ancestral feline diet, which is roughly 55 percent protein, 45 percent fat and only around 5 percent carbohydrate. A kibble diet delivers many times more carbohydrate than a cat was ever designed to process.
Cats cannot spare protein
Cats evolved eating multiple small, protein-rich meals throughout the day, so their bodies assume protein is always available. Because of that, a cat has no protein-sparing mechanism. Protein sparing is a defence the body uses to prioritise carbohydrate and fat for energy so that valuable protein is protected rather than burned as fuel. Dogs and humans on a high-carbohydrate, low-protein diet can switch over to burning carbohydrate and fat and spare their protein.
A cat cannot do this. Its internal engine is hardwired to burn protein for energy. When a cat is fed high-carbohydrate kibble, it still cannot switch to carbohydrate for fuel, so if the diet is short on usable protein the cat begins breaking down its own muscle, organs and amino acids to keep going. For an omnivore, protein is a building block that can be used for fuel when needed. For a cat, protein is the fuel, and it must keep burning even if that means burning the body itself.
Cats need specific amino acids that only meat provides
Cats have a remarkably high protein requirement. An adult cat needs roughly two to three times more dietary protein than an adult omnivore. On top of that, cats depend on several amino acids that come almost entirely from animal tissue and cannot be supplied as effectively by a plant-based, kibble-style diet.
| Amino acid | Why cats need it | What a shortage can cause |
|---|---|---|
| Taurine | Heart function, vision and reproduction. Cats cannot make enough of their own and use it up quickly in the liver. | Blindness, heart disease (dilated cardiomyopathy) and reproductive failure |
| Arginine | Runs the urea cycle that clears ammonia, a toxic by-product of using protein for energy. | A rapid, potentially fatal build-up of ammonia. Cats cannot make enough themselves. |
| Methionine & cysteine | Used for energy, and to build coat and the felinine cats use for scent marking. | Poor coat and skin condition |
| Tyrosine | Makes the melanin pigment in a cat’s fur. | A black cat’s coat can fade to a rusty, reddish brown, often a sign plant protein has replaced meat |
Cats have a low thirst drive
Cats descend from desert-dwelling ancestors, so they have a blunted sense of thirst and were never meant to drink much from a bowl. In the wild they get almost all of their water from prey, which is about 70 to 75 percent moisture. When a cat eats dry kibble, its instincts assume that food already carries plenty of water, so it only drinks a little to top up. The problem is that kibble has had nearly all of its moisture stripped out, so that small drink falls well short. A cat on dry food often takes in only about half the water it needs, leaving it in a state of constant, low-level dehydration that sets the stage for urinary problems.
Why isn’t dry kibble a good diet for cats?
Because kibble is high in exactly the nutrient cats are least able to handle: carbohydrate. As we have seen, a cat’s ancestral diet sits in the single digits for carbohydrate, with the rest coming from protein and fat. Most dry cat foods contain roughly 30 to 60 percent carbohydrate, which for a cat is a slow-burning metabolic problem. Pet food labels rarely state the carbohydrate content directly, so it often goes unnoticed.
You can estimate it yourself. On the guaranteed analysis panel, use this formula:
Run that on a typical dry food and the carbohydrate figure is often eye-opening. Here is what a steady diet of that carbohydrate does to a cat.
What health problems can a high-carb kibble diet cause in cats?
Feeding a cat against its biology takes a toll over time. The five conditions below are among the most common we see linked to long-term, high-carbohydrate dry feeding.
1. Obesity and the trap of “light” diets
Obesity is the single most common nutritional disorder in cats today, with an estimated 25 to 30 percent of cats overweight. The main driver is free access to highly palatable, carbohydrate-rich kibble, and obesity opens the door to other chronic illnesses such as diabetes and arthritis. The instinct to reach for a “light” food can make things worse, because manufacturers usually cut calories by packing the food with fibre rather than lowering the carbohydrate. That fibre is not digestible and moves through the gut quickly, sweeping nutrients like protein along with it. Because a cat needs protein for energy, it starts burning its own muscle instead. The cat may lose weight, but it loses muscle rather than fat, which is a poor outcome.
2. Type 2 diabetes
Every time a cat eats kibble, the carbohydrate is quickly converted to glucose and the blood sugar spikes. The pancreas releases insulin to move that glucose into the cells. Repeated spikes, meal after meal, gradually make the cells numb to insulin, so the pancreas has to pump out more and more to force the sugar down. Eventually the insulin-producing cells burn out, and the cat becomes diabetic. Research from Professor Jacqueline Rand’s group at the University of Queensland has shown that switching diabetic cats to a strict high-protein, low-carbohydrate diet can cut their insulin needs by more than half, and in many cases lets them stop insulin altogether.
3. Urinary tract disease and bladder stones
Because cats on dry food live in constant mild dehydration, they produce small volumes of very concentrated urine. That concentrated urine is the perfect setting for crystals to form. Those crystals irritate the bladder wall and can lead to feline lower urinary tract disease, painful inflammation, infections and bladder stones. A moisture-rich diet is one of the simplest ways to protect the urinary tract. For more on this, International Cat Care is a reliable resource.
4. Inflammatory bowel disease and a leaky gut
A cat’s gut is home to a community of microbes suited to digesting protein and fat. Feed a diet high in carbohydrate (above about 30 percent) and that balance shifts. The gut becomes more acidic, which favours unhelpful bacteria, and combined with the denatured proteins, flavourings and preservatives common in kibble, the immune cells lining the gut settle into a state of chronic low-grade inflammation. Over time this shows up as ongoing vomiting, diarrhoea, food intolerances and inflammatory bowel disease, which can be a precursor to gastrointestinal lymphoma.
5. Dental (periodontal) disease
It is a myth that dry kibble cleans a cat’s teeth. When a cat bites a biscuit, it simply shatters, with no real scrubbing action. Worse, the starch mixes with saliva into a sticky paste that coats the teeth and works under the gumline, speeding up tartar build-up, gum recession and painful resorptive lesions. Regular dental checks matter far more for oral health than any biscuit ever will.
What should you feed your cat instead of kibble?
Feed a species-appropriate diet that is high in protein, high in moisture and low in carbohydrate. That rules out dry kibble as a staple. In practice, the best options are gently cooked food, good quality canned (wet) food, and appropriate raw meat. Use the table below for a quick comparison, then read on for how this looks at each life stage.
| Food type | What it is | Best for | Watch-outs |
|---|---|---|---|
| Gently cooked | Fresh meat, organs and vegetables lightly cooked to a balanced formula, then frozen | An everyday staple, fussy or sensitive cats | Costs more than kibble, needs the fridge or freezer |
| Canned / wet food | Complete wet food with high natural moisture | An easy, high-moisture staple for most cats | Choose high-protein, low-carbohydrate formulas; check the label |
| Raw (commercial or home) | Uncooked meat, bone and organ prepared to a balanced formula | Cats that take to raw; a natural dental benefit | Freezer space, safe handling, and a properly balanced recipe |
| Dry kibble | High-heat extruded dry biscuit | Convenience and an occasional treat only | High carbohydrate, low moisture, least suited to cats |
Feeding kittens
Start kittens on a premium gently cooked diet (such as Tyga) or a good quality canned food. This is also the time to introduce different tastes, textures and proteins, since kittens are far more open to variety than adult cats, so vary the brand, formulation and protein source, always changing gradually. Feed small, frequent meals rather than one or two large ones. Milk can be given as an occasional treat if the kitten is not lactose intolerant, but it is not necessary (specially formulated kitten milk, not cow’s milk, which most kittens cannot digest). From around 12 weeks, you can begin introducing raw food in place of some meals a few times a week, such as fresh chicken wings or lamb cutlets (lamb can be fed raw, or frozen then thawed to kill toxoplasma). Commercially prepared raw food, such as Raw and Fresh, is another option. Keep raw to no more than about 10 percent of the diet at this early stage, wash your hands after handling it, and keep up routine intestinal worming. For a healthy start overall, see our kitten care service.
Feeding young adult cats
From about 6 to 8 months, move cats onto more natural food such as raw or gently cooked, phasing out dry food completely if it was ever fed. Aim for at least half the diet to be whole foods that need chewing. Premium dry food, if used at all, should only be a small treat. The rest can be a good quality canned food. As a rough guide, a young adult cat needs about 85 to 100 grams of canned food twice daily, which can be swapped for a chicken wing, a chicken drumstick or a lamb cutlet. Very active cats may need more. Feeding a gently cooked diet (such as Tyga) or a raw diet (such as Raw and Fresh) exclusively is ideal, and rotating the protein source adds valuable variety.
Feeding older cats
Older cats, from around 10 years, can be fed much like young adults, just in smaller amounts to match their lower activity. Keeping a senior cat lean matters, because carrying extra weight shortens a cat’s life. Regular check-ups become more important with age too, so consider pairing a good diet with our senior cat care.
How do I get my cat to drink enough water?
Because cats have such a low thirst drive, a moisture-rich diet does most of the work, which is another reason wet and fresh foods beat dry. Beyond that, always provide free access to fresh water and learn how your cat likes to drink. Many cats prefer running water, so a pet fountain can help, and some dislike the taste of chlorine. Boiling water in a kettle and letting it cool will drive off much of the chlorine, which can make it more appealing.
How do I switch my cat from kibble to fresh food?
Slowly, and without stress. Cats can be famously suspicious of new food, so make the change gradually over one to two weeks, mixing a little more of the new food into the old at each meal. Offer food at warm, body-like temperature to bring out the aroma, and feed set meals rather than leaving food out all day. If your cat is stubborn, do not force it or let it skip meals for long, since cats that stop eating can become unwell quickly. This is exactly the kind of thing we can guide you through, so talk to us before you start.
Let’s make a nutrition plan for your cat
Moving your cat from dry food to fresh, high-protein, high-moisture nutrition is one of the most powerful things you can do for its long-term health, and you do not have to work it out alone. Having trained in fresh food formulation, I can help you build a safe, balanced diet tailored to your cat’s age, health and tastes across both Lynbrook Vet and Berwick Clyde Vet. Give us a call or book a nutrition consultation, and let’s give your masterpiece the long, healthy life it deserves.
Frequently Asked Questions
Is dry food bad for cats?
Dry kibble is the diet least suited to cats. Cats are obligate carnivores that handle carbohydrate poorly, yet most kibble is 30 to 60 percent carbohydrate and very low in moisture. Over time, that can contribute to obesity, diabetes, urinary disease and dental problems. High-protein, high-moisture food is a better fit.
Are cats really obligate carnivores?
Yes. A cat’s body can only run properly on a meat-based diet. Cats lack the enzymes to digest much carbohydrate, cannot spare protein for energy, and need amino acids like taurine and arginine that come from animal tissue. They are built around highly digestible protein and fat, not starch.
What is the best food to feed a cat?
A species-appropriate diet that is high in protein and moisture and low in carbohydrate. In practice, that means gently cooked food, good quality canned (wet) food, or appropriately balanced raw meat, chosen to suit your cat’s life stage. Dry kibble is best kept to an occasional treat, if used at all.
Can a high-carbohydrate diet cause diabetes in cats?
It can contribute. Carbohydrate-heavy kibble causes repeated blood sugar spikes, and over time the cells become resistant to insulin until the pancreas is exhausted. Research shows that switching diabetic cats to a strict high-protein, low-carbohydrate diet can cut insulin needs by more than half, and sometimes stop them entirely.
How do I get my cat to drink more water?
Feed a moisture-rich diet, since wet and fresh foods provide most of a cat’s water. Always offer fresh water, and learn your cat’s preference. Many cats like running water, so a pet fountain can help. Boiling and cooling tap water removes much of the chlorine some cats dislike.
How do I switch my cat from kibble to fresh food?
Go slowly over one to two weeks, mixing a little more new food into the old at each meal. Serve food warm to boost the aroma and feed set meals. Do not let a reluctant cat skip meals for long, as cats can become unwell quickly. Ask your vet for help if needed.
