Dr.habil. Dr. Seronei arap Chelulei Cheison

Thursday, 8 October 2026

Would You Cook a Delicious Poison for Your Child?

Would You Cook a Delicious Poison for Your Child? On home-cooked pet food: how human culinary instinct can make a meal delicious to us, dangerous to the animal, and still leave out what a cat or dog actually needs.

On a recent visit to a home in the countryside, the owner told me, with real pride, how they cook for their German Shepherds. They go to the butcher for bones, bring them home, add a generous helping of onions, and simmer the pot overnight until the kitchen fills with the smell of it. A broth made slowly, by hand, out of love, for animals treated as family. It was described to me the way a good cook describes any dish they are proud of, and I did not have the heart, in that moment, to say what I knew.

Because that broth, made with such care, is close to the most efficient way I can think of to poison a dog.

Not through any carelessness. Quite the opposite. Every step in it is a step a thoughtful human cook would take. The long simmer that deepens a stock. The onions that give a broth its savoury base. The patience of leaving it overnight. These are the instincts of someone who knows how to make food taste good, applied with devotion to an animal they adore. The trouble is that the animal is not a human, and some of the very things a human cook reaches for to make that broth more delicious can make it dangerous to the dog it was lovingly made for.

And it is not only a rural habit, or an old one. In the cities, a growing number of devoted owners distrust the commercial food on the shelf, suspect the factory and its processing of hiding something toxic, and resolve to feed their pets the way they feed the rest of the family, with real food, cooked at home, by their own hands. The impulse is a good one, and the suspicion is not always wrong. But a person who has decided that the factory's food is poison, and who then seasons the home-cooked alternative the way they would season their own dinner, can end up doing the very thing they were trying to avoid, because the human kitchen contains perfectly ordinary ingredients that another species may not tolerate.

So the question this Conversation turns on is an uncomfortable one for anyone who loves an animal enough to cook for it. When we make our pets a meal with our own hands, whose palate are we actually cooking for, and are we sure the thing that would delight us is not quietly harming them?

Movement I

THE UNWRITTEN ART

Before we go near the harm, it is worth pausing on the skill, because the skill is real and almost everyone has it.

There is an art to making food pleasurable, and the remarkable thing about it is how little of it is taught. A person who has never read a recipe or studied a cuisine still knows, somehow, the moves that turn mere sustenance into a meal worth sitting down for. A pinch of salt to wake a dish up. A splash of soy, or a little of the savoury powder that deepens everything it touches. Onions and garlic softened in fat until the whole house smells of dinner and the appetite arrives before the plate does. Something acid to brighten, something sweet to round, a glass of wine beside it to loosen the evening, and a small bitter coffee at the end to settle the stomach and sharpen the mind. None of this is written down anywhere the cook consulted. It is carried in the hands and the nose, passed from kitchen to kitchen, obeyed by the unschooled as faithfully as by the chef.

The art of making food delicious is the one cookery almost everyone knows without being taught.

And it works, because it is tuned, over a very long time, to the human animal. Our appetite rewards salt because our ancestors had to seek sodium out, and rewards sweetness because sweetness meant ripe fruit and quick energy; those are ancient biology. Layered over them is a great deal of culture, the acquired human loves of the sharp smell of alliums, of a little wine with dinner, of a bitter coffee at the end, tastes we are not born craving but learn, in our own kitchens, to find delicious. Some of the cook's instincts are biology, some are culture, and most are now so familiar that the cook no longer needs to know which is which. When we say a dish is delicious, we mean it has satisfied that whole inherited and acquired human apparatus at once. The home cook is, in this sense, a kind of intuitive scientist of the human palate, running an experiment they never designed and getting it right by feel.

So when that same cook decides to make something for the animal at their feet, they do the natural thing. They reach for the only art they have. They cook for the pet the way they cook for the family, with the same hands, the same instincts, the same levers, because those levers have never once failed them at a human table. Why would the dog be any different? It has a mouth, it gets hungry, it clearly enjoys its food. The assumption is so quiet and so reasonable that it is barely an assumption at all. It is simply what everyone knows. And it is exactly here, in the gentlest and most loving transfer of a skill from one table to another, that the whole thing goes wrong. Because the levers the cook is pulling were built for a different animal. What if the instrument that has never failed at the human table is the wrong instrument entirely, the moment the eater is not human?

Movement II

THE SAME GESTURE, A DIFFERENT BODY

Return, then, to the broth, and watch what each loving step actually does once the eater is a dog.

The onions come first, and they are the gravest of it. Onions, like garlic, leeks and chives, belong to a family of plants that carry sulfur compounds harmless to us and dangerous to dogs and cats. Inside the animal those compounds become reactive agents that attack the red blood cells, damaging them until the body destroys them faster than it can make them, a condition called haemolytic anaemia. The cook who adds onions for savour is, without the faintest idea of it, adding the most obvious toxic hazard in the pot. And three details turn an unlucky ingredient into something closer to a trap. The first is that cooking does not make the onion safe; raw, cooked and concentrated forms can all cause the injury, so the long simmer that a cook trusts to improve a dish does nothing to remove the hazard. The second is that the harm can also follow repeated smaller exposures, which is exactly the pattern a broth made in a large pot and fed across several days can create. And the third is the cruelest. The damage is delayed, often by days, so the dog does not fall ill at the bowl where the cause would be obvious. It sickens later, by which time the broth is long forgotten, and the one person most likely to connect the two, the devoted cook, is the last to suspect the thing they made with love.

The onion that deepens the broth for us can turn the same loving meal into a hazard for the dog.

And the onion is not alone. Walk back along the human cook's toolkit and an uncomfortable pattern appears: some of the most ordinary ingredients in our kitchens cross the species boundary very differently from the way they sit with us. The square of dark chocolate we might think a kind treat carries theobromine, a stimulant we clear easily and dogs clear only slowly, so it lingers and builds and can, in sufficient amount, disturb the heart and the nervous system. There is a small biological irony here: cats are susceptible too, but their lack of sweet taste and their different, more discriminating feeding behaviour make the dog by far the more frequent chocolate patient, which is the argument of the last Conversation surfacing again at the family table. A few grapes or raisins, innocent at the human table, can cause acute kidney injury in susceptible dogs; tartaric acid is now a leading explanation, but individual risk remains unpredictable enough that an exposure should never be treated casually. And the grape is worth lingering on, because it is rarely cooked into anything. It is shared. Picture the family picnic, the parents idly eating grapes while the children run loose across the grass, and the dog that stayed, patient and good, at the edge of the blanket. Someone holds out a grape, a small reward for its steadiness, a way of saying you are one of us, have some of what we are having. That gesture is the purest expression of the whole impulse this essay is about, the animal folded into the family and offered the family's food, and it falls on a fruit whose risk to an individual dog remains disturbingly unpredictable.

The grape held out to the dog is not a meal. It is a welcome, offered on a fruit whose risk no one can predict.

None of these is an exotic poison kept in a locked cabinet. They are the ordinary furniture of a human kitchen, the things a good cook reaches for precisely because they make food taste of care.

So the pattern is not that careless owners harm pets while careful ones do not. It is stranger and more interesting than that. Culinary competence does not automatically transfer across species. The skills that make a person good at feeding humans, the instinct for seasoning, for depth, for the touches that signal care, are instincts about the human body and the human palate, and they carry no built-in knowledge of which of their pleasures are, to another animal, hazards.

Skill at the human table is real. It simply does not know which of its pleasures cross the species line.

A person can be an excellent cook and know nothing of the fact that onions injure a dog's blood, not through carelessness, but because nothing in the art of human cooking was ever required to teach them. Which leaves a genuinely unsettling question for anyone who has ever cooked for an animal out of love. If the competence we trust at the human table carries no knowledge of the animal's body, then what, exactly, has our skill been skill at?

Movement III

THE PROJECTION

Step back from the stove, because the mistake in the broth is not really a mistake about onions. It is a mistake about the animal, and it is the same mistake the whole of this series has been circling, arriving now in the most intimate place it could.

A recent Conversation argued that a cat is not a small dog, that we had quietly treated feline palatability as the canine kind with the volume turned down, and that the two animals in fact taste, smell and judge the world through different biology. The home cook makes the identical error, one rung further out. The pet is not a small human. The dog at the table is not a person with fur and a shorter vocabulary, running the same palate on the same chemistry and simply unable to ask for the salt. It is a different animal, with a different body, for which our food is not a smaller portion of the same thing but, in places, a different and dangerous substance. We shrank the human down, kept our own palate, and handed the result across the table as though love could make up the difference in biology. It cannot. Biology does not grade on intention.

We decided the pet was family. We forgot that family does not mean the same species.

And this is where the thread that has run through every one of these Conversations pulls tight. Palatability, we have said again and again, does not live in the food. It is not a property sealed inside a recipe, portable to whatever eats it. It is a response, assembled in a particular animal, by a particular biology, out of signals that animal's own body decides how to read. The formulator who forgot this built foods tuned to the wrong species. The clinician who forgot it misread the sick animal at the bowl. And the home cook who forgets it does something at once more loving and more dangerous than either, because the home cook is not running a trial or filling a bowl on a schedule. The home cook is expressing devotion, with their own hands, at their own table, and has every reason to believe that devotion is enough. It is the purest version of the error, and the one with the sharpest edge, because here the gap between what we intend and what the animal receives is not a matter of market share or clinical outcome. It is a matter of whether the animal is harmed by the very act meant to cherish it.

There is a hard thing to say here, and it is not a defence of anyone's commercial interest, only an observation about knowledge. Commercial petfood is not safe merely because it came from a factory, just as home-cooked food is not unsafe merely because it came from a kitchen. The difference that matters here is narrower and quieter than the argument between the two usually allows. Formulated petfood can draw on species-specific nutritional and toxicological knowledge that the ordinary human cook was never expected to possess, the knowledge that onions injure a dog's blood, that a cat's body has requirements a dog's does not, that there are things our food contains which theirs must not. That knowledge is not love, and it is no substitute for it. But when we reject formulation simply because it is formulation, we risk throwing away not only the processing we distrust but knowledge we did not know was there. And there is a second blindness beneath the first, quieter and in its way larger. Everything so far has been about what the loving cook puts in, the onion, the chocolate, the grape. But a home-cooked bowl can contain not one of those, not a single recognised toxin, and still fail the animal, because the danger in the home kitchen is not only what we add. It is also what love cannot tell us is missing. A dog or a cat needs a particular balance of calcium against phosphorus, a set of trace minerals, the right fats, certain vitamins, and, for the cat, enough dietary taurine, because its own synthesis cannot meet its requirements. None of these announces its absence. A broth can smell wonderful, be eaten with joy, contain nothing harmful, and quietly starve the animal of something its body cannot do without, over months, invisibly. The human palate was never an instrument for detecting a missing trace mineral. It was built to enjoy a meal, not to audit one.

So the question this movement leaves is not whether to cook for the animals we love. It is whether love, by itself, has ever been enough to feed them safely, or whether it has always needed something it does not contain.

Movement IV

FEEDING WHAT YOU LOVE

Would you cook a delicious poison for your child?

The question sounds absurd, even cruel, and that is the point of asking it, because the people this essay is about would answer no without a breath of hesitation, and yet some of them, without knowing it, may be putting into a beloved animal's bowl ingredients they would be horrified to recognise as dangerous to that species. They have decided, and rightly, that the animal in their home is family, a child in all the ways that matter to the heart. And then they cook for that child the way they cook for themselves, and prepare the bowl according to the same culinary instincts they use for their own plates, and set down, with love, a dish that is delicious to them and may be dangerous to the one eating it. The language of the fur baby and the family member turns out to carry a trap inside it, because if the pet truly is a child, then the loving broth is not a sweet indulgence. It is a delicious poison, cooked for a child, by a devoted parent who would be horrified to learn what they had made.

If the pet is truly family, then the loving broth is a delicious poison cooked for a child.

None of which is an argument against cooking for the animals we love, and it would be a poor reading of this essay to walk away from the stove in guilt. The impulse to feed your own with your own hands is one of the oldest and best things we do, and it deserves better than to be abandoned out of fear. What it does not deserve is to be trusted blindly. The love is not the problem. The love is the whole reason to get this right. The problem is only ever the quiet assumption that rides along beside the love, the belief that a creature we hold as family must therefore share our palate, our chemistry, our idea of what a good meal is. Strip that assumption out and the devotion remains, intact and admirable, needing only to be pointed at the right animal.

And that is a solvable thing, though not by this essay, which can diagnose the mistake but has no business pretending to be a recipe. The knowledge the home cook lacks exists. It is held by veterinarians and appropriately qualified veterinary nutrition specialists, by the people whose work is precisely to know which of the kitchen's pleasures are hazards and how a home-cooked diet can be made complete and safe rather than merely heartfelt. A person who wants to cook for their pet can learn what a cat is, what a dog is, what their bodies can and cannot do with the things we eat, and can build a table that honours both the love and the biology. The cooking need not stop. It only needs to start from the animal rather than from us.

Because the whole of this long conversation comes down, in the end, to a single quiet correction. We have spent these essays saying that palatability lives not in the food but in the animal that receives it, and nowhere is that truer, or more tender, than at the family table, where the food is made of love and the animal is the one we would least wish to harm. The table set with love is a good table. It only has to be set, at last, for the animal that is actually going to eat from it.

References

1. Cortinovis, C. & Caloni, F. (2016). Household food items toxic to dogs and cats. Frontiers in Veterinary Science 3:26. doi:10.3389/fvets.2016.00026

2. Salgado, B.S., Monteiro, L.N. & Rocha, N.S. (2011). Allium species poisoning in dogs and cats. Journal of Venomous Animals and Toxins including Tropical Diseases 17(1):4-11. doi:10.1590/S1678-91992011000100002

3. Eubig, P.A., Brady, M.S., Gwaltney-Brant, S.M., Khan, S.A., Mazzaferro, E.M. & Morrow, C.M.K. (2005). Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002). Journal of Veterinary Internal Medicine 19(5):663-674. doi:10.1111/j.1939-1676.2005.tb02744.x

4. Wegenast, C.A., Meadows, I.D., Anderson, R.E., Southard, T., González Barrientos, C.R. & Wismer, T.A. (2022). Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins. Journal of Veterinary Emergency and Critical Care 32(6):812-816. doi:10.1111/vec.13234

5. Stockman, J., Fascetti, A.J., Kass, P.H. & Larsen, J.A. (2013). Evaluation of recipes of home-prepared maintenance diets for dogs. Journal of the American Veterinary Medical Association 242(11):1500-1505. doi:10.2460/javma.242.11.1500

6. Pion, P.D., Kittleson, M.D., Rogers, Q.R. & Morris, J.G. (1987). Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy. Science 237(4816):764-768. doi:10.1126/science.3616607

7. van der Vyver, Y., Paul, A., Blecker, C. & Danthine, S. (2026). Gaps and controversies in feline food palatability. Animals 16(17):2721. doi:10.3390/ani16172721

About the Author

Dr. rer. nat. habil. Dr. Seronei Chelulei Cheison is the founder and Chief Executive Officer of Sinonin Biotech GmbH, where he works with petfood companies on palatant sourcing strategies, the innovation of palatability enhancers, and the design of palatability assessment. A trained food enzymologist, he led alternative protein and palatant development at Mars Petcare before founding Sinonin, and his research on protein chemistry spans two decades, a doctorate from Jiangnan University, and a habilitation from the Technical University of Munich.

Sinonin Biotech GmbH is a partner in the ZEST project (Grant Agreement No. 101157382) and the PROSCALE project (Grant Agreement No. 101288362), both funded by the Circular Bio-based Europe Joint Undertaking (CBE JU) under the European Union's Horizon Europe research and innovation programme. Views and opinions expressed are those of the author only and do not necessarily reflect those of the European Union or CBE JU. Neither the European Union nor the granting authority can be held responsible for them.

Thursday, 1 October 2026

A Cat Is Not a Big Dog: Why Petfood Palatability Is Species-Specific

A Cat Is Not a Big Dog. The Friday Conversation No. 11. A cat and a dog facing a single food bowl, with two different streams of aroma and taste signals rising from it toward each animal.

Why petfood palatability is species-specific. A cat is not a small dog in the liver, where a drug tolerated by one species can be dangerous to the other. This essay asks whether we have remembered that at the bowl.

There is a tablet in almost every home that makes the point rather brutally. Paracetamol is a familiar medicine for people, and can be used therapeutically in dogs under veterinary supervision. In cats, the same molecule can be dangerously toxic. The difference is not in the tablet. It is in the animal receiving it.

Veterinary medicine learned this a long time ago. Species is not a matter of scale. A cat is not a dog made smaller, any more than a dog is a wolf brought indoors and shrunk to fit the sofa. Their biology diverges in places that matter, and what one species can metabolise, tolerate or use safely cannot simply be carried across to the other. A cat's liver, in this instance, lacks the machinery a dog's relies on to break the drug down and clear it, so what leaves one animal quietly builds up in the other. We accept the lesson readily when the consequence is toxicity.

At the bowl, we have sometimes been less careful.

A cat and a dog can be offered the same food, carrying the same volatile compounds, the same peptides and amino acids and nucleotides and fats. On the analysis sheet the stimulus is identical. Biologically it is not, because it arrives at two different sensory systems, shaped by two different evolutionary histories, equipped with different receptors, different feeding behaviours and different expectations of what a meal is supposed to signal. The formulation may be identical. The sensory information arriving at the brain is not.

So this Conversation begins with a proposition that veterinary medicine already knows by heart, and that petfood palatability has been slower to take seriously. A cat is not a big dog. Not in the liver, where the difference can be measured in survival. And, this essay will argue, not at the bowl either. Which leaves a question worth carrying through everything that follows: when a cat turns from a food that a dog accepts, what exactly have we learned, about the food, or about the difference between the two animals we offered it to?

Movement I

SAME BOWL, DIFFERENT ANIMAL

Start not with the senses but with the two histories that shaped them, because the difference between a cat and a dog at a bowl is older than either animal's tongue.

The dog descends from a pack hunter and scavenger, an animal that ate when it could and often could not, that pulled down large prey together and gorged, then went without. That past is written into the dog we feed, an animal broadly built to take a large meal quickly and to wait a long time for the next, tolerant of a bowl that arrives once or twice a day, and inclined to try what it finds, because a scavenger that samples widely eats more often than one that does not. The cat descends from something quite different, a solitary hunter of small prey, an animal that caught a mouse, ate it, and hunted again, many times across a day and a night. It was never a gorger, because a mouse is not a feast, and its body records the difference at the plainest level. A cat's stomach is small, holding only a few hundred millilitres, restricted enough that the natural pattern is many small meals rather than a few large ones. In the wild the cat takes something like a dozen or more tiny feeds across the day, five to seven grams at a time, little and often, the rhythm of the hunt.

The dog was built to gorge and wait. The cat was built to graze the day in small returns.

Hand these two animals the same bowl, on the same once-a-day schedule, in the same quantity, and something quietly odd has happened, though it is so ordinary we never notice it. We have asked the cat to eat like a dog. Much of what frustrates the owners of cats, the food left half-eaten and returned to through the day, the refusal of a large single serving, the picking and grazing that reads as fussiness, is the cat doing exactly what it was built to do at a bowl designed around the dog's pattern rather than its own. And the cat is warier of the new than the dog, because a specialist hunter of fresh prey is safer treating the unfamiliar with suspicion where a scavenger profits from trying whatever it finds. So it is worth asking, before we call the cat difficult, whether we have ever actually offered it a cat's meal, or only a dog's meal that a cat was expected to accept.

The difference runs deeper than schedule and quantity, down to what each animal is trying to achieve when it eats. Left to choose freely among foods, neither animal simply eats what tastes best. Each eats toward a target, a particular balance of protein and fat that suits its biology, and the two targets are not the same, the dog's leaning toward fat and the cat's toward protein, close to the composition of the prey it evolved to catch. The striking part is what happens when taste and target disagree. In studies where cats were offered foods of different flavours and different nutrient content, they chose at first by flavour, exactly as we would expect, and then, over the following days, learned the compositions and shifted their choices to reach their nutritional target, overriding the very flavours that had won the first meal. Read that slowly, because it unsettles a comfortable assumption. For the cat, in the end, palatability can lose to need. The tastiest option does not necessarily win if it pulls the animal away from where its body is trying to go, and that is not a fact one could ever recover from a single first-choice test.

It is worth conceding at once that the line is cleaner than nature is. A Chihuahua is not a Great Dane, and on several of these measures a tiny toy dog with a small stomach and a delicate appetite sits closer to a cat than to a mastiff that bolts a bucket of food and looks up for more. Breed, size, age and temperament all move an animal along these axes, and the within-species range can be as wide as the gap between species. The claim is not that every cat differs from every dog on every count. It is that the cat, as a type, is built along a different line from the dog, as a type, and that the differences are biological and consistent rather than matters of mood. So before we ask why the cat is harder to please, a prior question is worth holding: harder to please than what, and measured against whose idea of a meal?

Movement II

THEY DO NOT TASTE THE SAME WORLD

If the two animals were shaped by different pasts, the deepest mark that past has left is on the senses that meet the food, and here the differences are not of degree but of kind. Set the same bowl before a cat and a dog and, at the level of the nerves, two different foods are being received.

Begin with the plainest divergence, which is also the one most easily forgotten. The cat cannot taste sweetness. The receptor that detects sugars, which the dog carries and responds to, exists in the cat only as a broken gene, present in the genome but silent, switched off across evolutionary time in an animal that never ate anything sweet. This is not a mild preference against sweet things. It is an absence of the signal altogether, in the way a colour-blind eye receives nothing where another eye receives red. A sweet note that a dog leans toward reaches the cat as nothing at all. And it would be a mistake to fill that silence with our own vocabulary, because the risk throughout this territory is that we describe the animals' senses in the words of ours. Both cats and dogs respond to the savoury, meaty quality we call umami, but they do not reach it by the same route; the molecules that trigger it most strongly in a cat, abundant in fresh animal tissue, are not the same ones, or in the same proportions, that trigger it in a dog. The word is the same. The chemistry the word points to is not.

The formulation may be identical. The sensory information arriving at the brain is not.

If that is true of the one taste the two animals seem to share, what should we expect of a food built on the human assumption that savoury is savoury and sweet is a virtue, to whichever animal happens to eat it? The cat also judges with a strikingly small set of taste instruments, a few hundred taste buds where a dog has several times as many, and it would be easy and wrong to read that as a fainter version of the dog's palate. It is not weaker. It is narrower and more sharply tuned, an instrument built to make a small number of distinctions that matter to a hunter and to ignore much that does not. And because the palate gives it so little to work with, the cat throws the weight of the decision onto its nose. Even here the easy comparison misleads. The dog carries more scent receptors overall, and on that number alone one would call it the better-nosed animal, but the two noses are built for different jobs. The dog's is built to detect and to track, to find a faint scent across a field. The cat's is built to discriminate, to tell one close smell from another, and it carries several times as many of the specialised receptors that do that fine sorting. The dog's nose asks where is it. The cat's asks what exactly is it, and is it right. And because the cat can barely taste, that discriminating nose is not a helper to the meal decision. It is the meal decision.

The dog's nose is built to find the food. The cat's is built to judge it.

Then, if the food passes the nose, comes the mouth, and the cat's mouth is a set of prey tools the dog's is not. A dog's jaw can move sideways and grind; a cat's cannot. The feline jaw is close to a pure hinge, and the teeth behind it are blades, not millstones, shaped to shear meat from a carcass rather than to crush and chew. A cat has fewer teeth than a dog and none of the flat grinding surfaces, and so it does not really chew in the sense we mean; it slices and swallows, or rolls a piece to the side to break it. Even the tongue is a different tool, covered in backward-facing spines of keratin, the same material as the claws, a rasp built to strip meat from a bone where a dog's tongue is smooth. Salt, which flatters the human palate and is useful in the dog, is close to dead in the cat, an obligate carnivore that ate whole prey and was never short of sodium. At point after point, the same food is not the same food. It is warmed or cooled into a different aroma, met by a different palate, judged by a different nose, and handled by a different mouth. So the question that closes this movement is not whether cats and dogs differ. It is a harder one. How did we ever persuade ourselves that a signal built to please one of them would arrive, unchanged, at the other?

Movement III

THE PALATANT IS NOT THE MESSAGE

There is a way of speaking about palatability that treats it as a property a food simply has, a quality you can build into a recipe and then measure, the way you build in protein and then measure it. On that view a palatant is a thing you add to make a food more palatable, and palatability is what you have added. It is a comfortable picture, and it is wrong, and the two animals we have just been comparing are what expose it. Because here is the question the comparison forces. If the molecule leaving the bowl is the same, and the animal receiving it is not, where exactly does the palatability live?

Consider what a palatant actually is. It is a collection of signals, chemical and physical, aromas and tastes and textures, assembled to be detected. But a signal is not a message until something receives it, and detection is only half of what is happening at the bowl. The other half is interpretation, and interpretation belongs to the animal, not to the food. A molecule that lands on a receptor the cat does not have sends nothing. A molecule that lands on a receptor the cat has, but reads through the biology of a fresh-kill hunter, may mean something quite different to the cat than the same molecule means to the dog. The palatant does not carry its meaning inside it, sealed and portable, the way a number is carried on a specification sheet. Its meaning is made, each time, in the meeting between the signal and the animal that receives it. We said it of the drug at the start, and it holds just as firmly here. The difference is not, in the end, in the palatant. It is in the animal receiving the signal.

There is no such thing as a palatable molecule. There is a molecule, a receptor, an animal, and a response.

An earlier Conversation reached the same place from a different door. It argued that palatability does not reside in the food alone, that a diet is not palatable or unpalatable in the abstract but only to a particular animal, in a particular state, on a particular day. That was said of the individual patient, of how illness and appetite and memory change what a food means to the one animal in front of the bowl. This is the same truth read at the level of the species. If palatability does not reside in the food for a single sick cat, it does not reside in the food across the gulf between a cat and a dog either. It never lived in the molecule. It lives in the response, and the response is the animal's to give.

This is why the comfortable picture fails, and why it matters that it fails. If palatability were a property of the food, then a food made more palatable would be more palatable to whatever ate it, and the species of the eater would be a detail. But if palatability is a response, assembled freshly in each animal from signals its own biology decides how to read, then the species is not a detail at all. It is the thing that decides what the signals mean. So a food developed until it performs beautifully for one animal has been tuned, precisely, to one animal's way of reading it. What has it been tuned to, for the other? And how would we know, if the only animal we asked was the one it already suited?

Movement IV

ONE FACTORY, TWO BOWLS

None of this is news to the people who make pet food. Of course the industry develops separately for cats and dogs; of course it knows the two animals differ. The question is subtler, and it is about assumption rather than intent. When a discipline grows up around the easier subject, its habits form around that subject, and the habits travel quietly into the harder work without anyone deciding they should. The dog is the more forgiving eater, the one whose acceptance is simpler to win and simpler to read, and a great deal of what we know about testing food, about what a good result looks like and how to interpret a bowl, was learned where it was easiest to learn. The risk is not that we treat the cat as a dog on purpose. It is that a canine logic, built where the animal was accommodating, becomes the default logic, and is carried into feline work as though it were neutral.

Nowhere does this matter more than at the frontier the rest of this series keeps returning to, which is the replacement of familiar animal ingredients with new ones. When a formulator sets out to replace chicken with a protein from a fungus, an insect, a microbe or a plant, it is tempting to describe the task as swapping one protein for another. But a protein is never only a protein. It arrives with a whole constellation around it, a particular set of amino acids and peptides, of nucleotides and volatile compounds, of fats and physical characteristics, and that constellation is precisely what the animal's senses read. Change the source and you change the constellation, and you are no longer presenting the same message to be received. You are presenting a different one, to two different sensory systems, each of which will decide for itself what it means.

A protein is never only a protein. It is the whole constellation the senses read.

And here the species divide turns from a matter of biology into a matter of consequence. Suppose the new protein is tested and accepted by dogs, and performs well. That is a real result, and a welcome one. But when a palatant performs beautifully in dogs, what exactly have we learned about cats?

When a palatant performs beautifully in dogs, what have we learned about cats?

Less than we would like. The dog, with its broader tolerances, its functional sweet sense, its more forgiving nose and its scavenger's willingness, is the animal most likely to accept a substitution and least likely to notice what the substitution lost. A replacement that satisfies the dog has cleared the lower bar. Whether the same replacement has reconstructed, for the cat, the specific chemical world its narrow and exacting biology is tuned to detect, is a separate question, and the dog's acceptance does not answer it. This is why the palatability of alternative proteins is so easily underestimated. It looks like one problem, solved once the animals eat. It is at least two problems, and the one we are more likely to have solved is the one that was easier to begin with.

A replacement the dog accepts has cleared the lower bar. The cat's bar is a different question.

Step back, at the end, and look at the whole arrangement from the factory end of the chain. We put a cat and a dog under the same roof, call them both pets, formulate complete foods for both, coat those foods with things meant to make them desirable, and measure what disappears from the bowl. From that vantage it is natural to see two versions of a single problem, palatability, to be solved with one set of tools and confirmed with one kind of test. Evolution did not see two versions of one problem. It built two different animals, from two different pasts, reading the same bowl through two different sets of senses, wanting two different things from a meal and defending them in two different ways. A cat is not a small dog in the liver, where the wrong dose finds it out. It is not a small dog at the bowl either. And perhaps palatability, if it is to mean anything precise, has to begin not with the food, and not with the factory, but with the animal we are actually asking to eat.

References

1. Court, M.H. & Greenblatt, D.J. (2000). Molecular genetic basis for deficient acetaminophen glucuronidation by cats: UGT1A6 is a pseudogene, and evidence for reduced diversity of expressed hepatic UGT1A isoforms. Pharmacogenetics 10(4):355-369. doi:10.1097/00008571-200006000-00009

2. Li, X., Li, W., Wang, H., Cao, J., Maehashi, K., Huang, L., Bachmanov, A.A., Reed, D.R., Legrand-Defretin, V., Beauchamp, G.K. & Brand, J.G. (2005). Pseudogenization of a sweet-receptor gene accounts for cats' indifference toward sugar. PLoS Genetics 1(1):27-35. doi:10.1371/journal.pgen.0010003

3. McGrane, S.J., Gibbs, M., Hernangomez de Alvaro, C., Dunlop, N., Winnig, M., Klebansky, B. & Waller, D. (2023). Umami taste perception and preferences of the domestic cat (Felis catus), an obligate carnivore. Chemical Senses 48:bjad026. doi:10.1093/chemse/bjad026

4. Lei, W., Ravoninjohary, A., Li, X., Margolskee, R.F., Reed, D.R., Beauchamp, G.K. & Jiang, P. (2015). Functional analyses of bitter taste receptors in domestic cats (Felis catus). PLoS ONE 10(10):e0139670. doi:10.1371/journal.pone.0139670

5. Young, J.M., Kambere, M., Trask, B.J. & Lane, R.P. (2005). Divergent V1R repertoires in five species: amplification in rodents, decimation in primates, and a surprisingly small repertoire in dogs. Genome Research 15(2):231-240. doi:10.1101/gr.3339905

6. Montague, M.J. et al. (2014). Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication. Proceedings of the National Academy of Sciences 111(48):17230-17235. doi:10.1073/pnas.1410083111

7. Bradshaw, J.W.S. (2006). The evolutionary basis for the feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus). The Journal of Nutrition 136(7):1927S-1931S. doi:10.1093/jn/136.7.1927S

8. Hewson-Hughes, A.K., Hewson-Hughes, V.L., Colyer, A., Miller, A.T., McGrane, S.J., Hall, S.R., Butterwick, R.F., Simpson, S.J. & Raubenheimer, D. (2013). Geometric analysis of macronutrient selection in breeds of the domestic dog, Canis lupus familiaris. Behavioral Ecology 24(1):293-304. doi:10.1093/beheco/ars168

9. Hewson-Hughes, A.K., Hewson-Hughes, V.L., Miller, A.T., Hall, S.R., Simpson, S.J. & Raubenheimer, D. (2011). Geometric analysis of macronutrient selection in the adult domestic cat, Felis catus. The Journal of Experimental Biology 214(6):1039-1051. doi:10.1242/jeb.049429

10. van der Vyver, Y., Paul, A., Blecker, C. & Danthine, S. (2026). Gaps and controversies in feline food palatability. Animals 16(17):2721. doi:10.3390/ani16172721

About the Author

Thursday, 24 September 2026

Petfood palatability in veterinary diets: what the patient will eat

The First Mouthful, The Friday Conversation No. 10. A nutritionally complete veterinary diet in a bowl and a cat walking away, the challenge of feeding the animal that needs the food but may not want it.

The First Mouthful. The palatability challenge in veterinary diets: when what the animal needs to eat and what the animal wants to eat are not quite the same thing.

Somewhere today a nutritionist finishes a formula for a sick cat. Every number on the sheet is right. The phosphorus is where the failing kidney needs it, the protein carefully judged, the mineral and acid-base balance attended to, the energy and essential nutrients accounted for. It is, on paper, a small triumph of veterinary nutrition, a diet that could genuinely slow a disease and lengthen a life. And then it is put down in front of the cat, and the cat looks at it, and walks away.

Nothing on the sheet was wrong. A veterinary diet can be perfectly formulated for the disease and badly formulated for the patient, and the two are not the same achievement.

This is the quiet difficulty at the centre of therapeutic nutrition, and it is a different difficulty from the one an ordinary pet food faces. An everyday food is designed to be wanted, and if the animal wants it, the job is largely done. A veterinary diet is designed to be needed, and being needed is not the same as being wanted. The clinical target and the animal's appetite are set by different authorities that do not consult each other. The kidney has its requirements. The nose has its own. And a diet does not become therapeutic when the nutritionist finishes the formula. It becomes therapeutic when the patient eats it.

So the question this essay begins with is one the analytical sheet cannot answer, and it is worth asking plainly, because so much sophistication rides on it. When what an animal needs to eat and what it wants to eat are not quite the same thing, which of the two decides whether the medicine works?

Movement I

THE COLOURS THE DISEASE REMOVED

To see why this is hard, start with the question each kind of formulator is actually asking, because they are not asking the same one.

The developer of an ordinary pet food asks, broadly, a question of addition. What can I bring forward, or turn up, to make this food more attractive? That formulator is far from unconstrained, since nutrition, safety, processing, cost and regulation all bind the work, but within those bounds there is considerable freedom to chase the palate. The developer of a veterinary diet asks the same question of attraction inside a much narrower clinical corridor. What can I use without compromising what this food is supposed to do? The clinical target comes first and is not negotiable, and the palate has to be satisfied in whatever room is left over. One formulator works on a wide canvas. The other works on a canvas where the disease has already painted, in fixed colours that cannot be moved, and has taken several of the best colours away.

Consider what the constraint actually means. A phosphorus ceiling for a failing kidney is not a preference to be balanced against palatability; it is a wall. A hydrolysed protein selected for an elimination diet cannot simply be swapped for a familiar intact one to improve acceptance, because doing so may defeat the diagnostic or therapeutic purpose the diet exists to serve. The mineral balance a urinary diet must hit is a chemistry the formulation has to deliver, not an aspiration. In each case a lever that an ordinary formulator would reach for without a second thought has been bolted to the floor, and often it is precisely the lever that would most have helped the food be eaten. The disease does not just set the nutritional brief. It confiscates the tools.

The ordinary formulator asks what to add. The veterinary formulator asks what is left.

An earlier Conversation looked hard at the sick animal from the side of measurement, and found that intake is the least trustworthy thing we measure in exactly this patient, because the reliable hunger that lets us read an empty bowl as approval is the first thing many diseases take away. Grant all of that. This essay stands on the other side of the same problem and asks a different question. Not how we misread the sick animal at the bowl, but how we formulate for it at the bench, knowing the appetite we are formulating for may already be compromised before the food is ever set down. The measurement problem and the formulation problem are two faces of one difficulty, and this is the second face.

Which is why the challenge cannot be met by the reflex the phrase invites. Told that veterinary diets are hard to make palatable, everyone reaches for the same answer, that we should simply make them more palatable, work harder at the acceptance, push the appeal. That is not wrong, but it is not sufficient, and it may not always even be the right aim. So before we ask how to make a therapeutic diet more palatable, a prior question is worth sitting with. What, exactly, has each disease forbidden, and how differently does each one break the quiet agreement between what an animal needs and what it wants?

Movement II

FOUR WAYS TO BREAK THE AGREEMENT

Between what an animal needs and what it wants there is, most of the time, a quiet agreement. Fresh meat is both nourishing and delicious; the food that keeps the animal alive is the food it enjoys, and evolution arranged the overlap on purpose. Therapeutic diets are the places where that agreement breaks, and it is worth seeing that it breaks in four quite different ways, because the difference is the whole subtlety.

The renal diet breaks it by subtraction. To slow a failing kidney the formulation restricts phosphorus, the protein quantity and quality have to be judged carefully, and the rest of the formulation is built around maintaining adequate nutrition inside those limits. Each of those judgements is a clinical necessity, and several of them remove or constrain something the palate was using. The diet is asked to be appealing with several of appeal's usual instruments taken out of its hands, and it is asked to be so for an animal whose illness has often dulled its appetite before the bowl is even filled. Need and want here are not in conflict so much as starved of common ground.

The elimination diet breaks the agreement more sharply, almost cruelly. Its whole purpose is to feed a protein the immune system cannot recognise, either one the animal has never met or one hydrolysed into fragments less likely to retain the antigenic structures that provoke the reaction, so that the source of an allergy can be found or managed. Now consider the ordinary formulator's instinct, which is to reach for a familiar, savoury animal protein and the flavour systems built around it. Many of those the elimination diet simply cannot admit, because the familiar ingredient is the very kind of thing the trial exists to exclude. The most convenient tools of acceptance are ruled out by the diagnosis itself. And hydrolysis, which solves the immunological problem, does so only by creating a new sensory one, since the same cutting that hides the protein from the immune system can, as an earlier Conversation followed in detail, expose a bitterness the tongue reads all too well. The diet has to win acceptance with much of the usual toolkit closed to it, and with a process that can work against the palate even as it serves the diagnosis.

The most convenient tools of acceptance are the ones the diagnosis rules out.

The urinary diet breaks it in yet another way, by making the animal's own consumption the delivery mechanism. The point of the diet is to alter the urinary environment, through mineral composition, urine concentration and, where appropriate, urine pH, so that conditions become less favourable to the particular crystal or stone at issue. And that altered environment only reaches the bladder through what the animal actually eats and drinks. A urinary formula that is perfect on the specification sheet and left in the bowl protects nothing. Here need and want are welded together in an uncomfortable way, because the therapeutic effect is not delivered by the formula at all. It is delivered by the eating.

And then there is the obesity diet, which breaks the agreement most interestingly of all, by reversing the goal. Every diet so far wanted the animal to eat and struggled to make that happen. The weight-management diet needs the animal to be nourished and satisfied on fewer calories, and its whole purpose is undone if the result is simply that the animal eats more. The food still has to be palatable enough to be accepted, because a refused diet helps no one. But acceptance is not the same as maximum consumption, and here, for once, the therapeutic objective is plainly not to make the animal eat as much as it possibly can. Which forces the question the whole essay has been circling toward. If one therapeutic diet succeeds by being eaten more and another succeeds by being eaten less, can the aim of veterinary palatability really be, as we so easily assume, simply to make the animal eat as much as possible?

Movement III

THE FIRST MOUTHFUL

There is one more thing the specification sheet cannot hold, and it may be the most important of all. A diet is not eaten in the abstract. It is eaten by a particular animal, at a particular moment, and the moment matters as much as the food.

We are tempted to speak of a food as though palatability were a fixed property of it, as though a diet were simply palatable or unpalatable the way it is high or low in phosphorus. But an animal does not meet a food the way an instrument meets a sample. It arrives carrying a physiological state, a history of what it has eaten and how that turned out, and a memory, and for the therapeutic patient every one of those is likely to be working against the meal. The food designed for the sick animal very often first meets that animal on one of the worst eating days of its life, at the moment of diagnosis, when it feels least like eating, and is asked at that exact moment to accept something unfamiliar. This is why refusal at the bowl is not one problem but several wearing the same face. Sometimes the patient is rejecting the food itself. Sometimes it is rejecting the memory of what happened the last time it ate, a nausea the food has been unluckily paired with. And sometimes it is not rejecting the food at all, but is simply too unwell to want to eat anything. Those are three different problems, and clinical guidance is right to insist that the medical causes of a poor appetite be addressed before the food is blamed for it. Palatability, seen this way, is not a number stamped on the food. It is what happens in the meeting between a food in a particular state and an animal in a particular state, and the sick animal brings the harder half of that meeting.

Palatability does not reside in the food alone. It happens between this food and this animal, on this day.

So return, at the end, to the cat we began with, and to the perfect formula it walked away from. Notice what has and has not changed. The formulation has not changed. The analytical sheet, with every number in its place, has not changed. The disease has not changed. All the nutritional sophistication that could slow that cat's illness is still sitting in the bowl exactly as designed. Only one thing stands between that sophistication and the patient it was built for, and it is not a molecule, and it is not on any sheet. It is whether the cat eats.

We have spent a great deal of veterinary nutrition, and a great deal of real ingenuity, on the first half of a sentence, asking what the sick animal should eat. It may be time to give equal seriousness to the second half, which is quieter and less flattering to our chemistry, and asks only whether the sick animal will eat it. The first half is a question of knowledge. The second is a question of acceptance, and acceptance is where the knowledge either reaches the patient or fails to.

Because for the animal in front of the bowl, the old opposition dissolves. Eat to live and live to eat were never really opposites here. The eating is not a reward that follows the therapy or a pleasure separate from it. The eating is the therapy's first and non-negotiable step, the point at which everything the formulation knows either enters the animal or does not. A therapeutic diet left in the bowl cannot deliver the therapy it contains.

The treatment begins with the first mouthful.

References

1. Elliott, J., Rawlings, J.M., Markwell, P.J. & Barber, P.J. (2000). Survival of cats with naturally occurring chronic renal failure: effect of dietary management. Journal of Small Animal Practice 41(6):235-242. doi:10.1111/j.1748-5827.2000.tb03932.x

2. Magalhães, T.R., Corbee, R.J., Queiroga, F.L. & Lourenço, A.L. (2026). Acceptance and preference of a commercial dry renal diet in healthy cats: an in-home proof-of-concept trial. Journal of Animal Physiology and Animal Nutrition. doi:10.1111/jpn.70043

3. Ilias, N., Zaki, A.H.H., Awang Junaidi, A.H., Lau, S.F., Saufi, I. & Ajat, M. (2022). Palatability assessment of prescribed diets on domestic shorthair cats. Veterinary World 15(3):640-646. doi:10.14202/vetworld.2022.640-646

4. Magalhães, T.R., Lourenço, A.L., Corbee, R.J. & Queiroga, F.L. (2023). Clinical management of feline chronic kidney disease in Portugal: a questionnaire-based study. Journal of Feline Medicine and Surgery 25(11):1098612X231206125. doi:10.1177/1098612X231206125

5. Weber, M., Bissot, T., Servet, E., Sergheraert, R., Biourge, V. & German, A.J. (2007). A high-protein, high-fiber diet designed for weight loss improves satiety in dogs. Journal of Veterinary Internal Medicine 21(6):1203-1208. doi:10.1111/j.1939-1676.2007.tb01939.x

6. Berridge, K.C. & Robinson, T.E. (2016). Liking, wanting, and the incentive-sensitization theory of addiction. American Psychologist 71(8):670-679. doi:10.1037/amp0000059

7. van der Vyver, Y., Paul, A., Blecker, C. & Danthine, S. (2026). Gaps and controversies in feline food palatability. Animals 16(17):2721. doi:10.3390/ani16172721

About the Author

Thursday, 17 September 2026

Petfood palatability: Why amount eaten under-measures liking

Beyond the Bowl, The Friday Conversation No. 9. An empty pet bowl on a digital scale reading zero grams, 263 grams consumed, with a dog and a cat regarding it.

We measure too little, we discard too much, and we sometimes infer more than the measurement can support.

A family finishes a good dinner and carries the plates to the kitchen. Someone scrapes the last of the bones into a bowl and steps out to the kennel, where two dogs have heard the door and are already on their feet. The bones go over the fence. What follows is not dignified. There is a scramble, a scattering, a low warning growl, a snatched femur carried off at speed and defended against a sibling who wants it more than anything in the world. To watch them is to be in no doubt at all. The dogs love these bones.

Now move a few hundred kilometres to a room where the same enthusiasm is being manufactured on purpose. A commercial food has been developed, refined and tested to the point of exhaustion, precisely to predict that dogs will eat it eagerly and come back for more. And when the trial runs, they do. The bowls come back empty. The numbers are excellent. The food, by every measure the room can produce, is a success.

Both scenes end the same way. An empty vessel and an animal that ate what was there. On the record they look identical, and that is exactly the difficulty. The dogs may truly love those bones. But the scene at the fence cannot tell us how much of what we are watching belongs to the bones themselves, how much to hunger, how much to the brother competing for the same femur, and how much to the simple fact that food has suddenly appeared. If ravening for scraps and clearing a tested bowl leave the same trace, then the trace is holding more than one cause and telling us less than we think. Somewhere underneath the grams eaten is a question the grams cannot answer on their own.

What exactly did we measure?

Movement I

THE EMPTY BOWL

There is an extraordinarily simple instrument at the centre of petfood palatability science. A bowl. Sometimes two. We weigh the food before the animal enters. We put the bowl down. The animal approaches, smells, hesitates perhaps, begins to eat, stops, moves away, comes back, changes bowls, eats again and eventually leaves. We collect what remains and weigh it. Between those two weighings an astonishing amount of biology has happened, and at the end of it we are left with a wonderfully precise number. Grams eaten.

These methods have served the industry well. They are simple, reproducible and commercially meaningful, and if animals consistently eat more of one formulation than another, anyone developing petfood should want to know. I have relied on them, and I would rely on them again tomorrow. The point of this essay is not that the bowl is wrong. It is that the bowl is quiet about most of what it saw.

Because an empty bowl is a powerful commercial signal, and a powerful temptation. A food that goes uneaten has a problem, whatever its nutritional formulation, and I have argued throughout these Conversations that adequacy and acceptance are different problems. But we should be careful about what an empty bowl allows us to conclude, and the care begins with a fact so obvious it is easy to step over. Animals eat because eating is necessary. An animal needs energy and nutrients to stay alive, and hunger exists to make sure it goes and gets them. Feeding therefore sits at an awkward junction between physiological necessity and sensory reward, and a bowl weight cannot tell the two apart.

A dog that finishes its ration has shown that the food was acceptable enough to eat. It has not shown that the dog liked it, and the gap between those two statements is the whole of this essay. There is a difference between eating a thing, accepting it, preferring it and taking pleasure in it. The phenomena overlap, and we have a single word, palatability, that we allow to cover all of them, and then we let the measurement of the easiest one stand as evidence for the rest.

An empty bowl proves that food was eaten. It does not prove that food was loved.

So perhaps we are not only under-measuring palatability. Perhaps we are over-interpreting intake. And it is worth asking the question plainly, because the whole industry answers it a hundred times a day without pausing on it: when a bowl comes back empty, what exactly have we been entitled to conclude?

Movement II

EATS TO LIVE

Here is the distinction the bowl cannot draw, and everything else follows from it. A pet must eat to live. But it may also eat because eating is rewarding, and sometimes an animal will take more than its immediate energy needs simply because the food is good. For analytical convenience these are often discussed as homeostatic feeding, the eating that answers a bodily need, and hedonic feeding, the eating that answers pleasure, although the underlying systems interact extensively rather than operating as two independent switches. Our difficulty is that the empty bowl records both at once and distinguishes neither. When we place a single food in front of a hungry animal, we are watching the homeostatic drive with the hedonic reward folded somewhere inside it, unseparated. The animal that clears the bowl has told us it was hungry enough to eat what was there. How much it wanted that particular food, as opposed to food, is a question the empty bowl leaves open.

The two-bowl test exists partly to close that gap, and it is a real improvement, because it introduces a choice. Put A beside B and let the animal decide, and now we can see how it distributed its eating, and which bowl it went to first. If A takes 70% and B takes 30%, we have good evidence that under those conditions the animals put more of their eating into A. We usually say A was preferred, and that is fair. But notice what the test did. It moved us from an absolute question, will you eat this, to a relational one, given these two, which will you eat more of. Preference now needs a comparator, and change the comparator and A's apparent quality changes with it. A food can lose 40:60 against an exceptional rival and be entirely acceptable. Another can win 60:40 against a poor one while neither food stirs much enthusiasm at all. A preference test has no winner without a loser, and it still does not tell us the thing we might most want to know, which is how much the animal actually valued the food it chose.

And hunger is not a constant sitting politely outside the experiment. It is inside it. The animal arrives in a physiological state, hungry or nearing satiety, carrying a feeding history and a set of learned associations and a temperament of its own, and its metabolism is a participant in our test. A sufficiently hungry animal has a reason to eat before the question of attractiveness even arises, and as it eats and hunger fades, the balance between drive and food-specific reward shifts under us. Which raises an uncomfortable possibility. The first grams and the last grams of a meal may not mean the same thing. Nor need the first meal and the twentieth.

Hunger asks the animal to eat. Palatability helps decide what it wants to eat.

We need, then, to be disciplined about words, because there is a hierarchy hidden inside the one we use most loosely. Need is the baseline, the homeostatic pressure to eat at all. Acceptance is the animal's willingness to eat this food rather than refuse it. Preference is how it divides its eating between alternatives when offered a choice. Wanting is how hard it will work to obtain one food over another. And liking, at the far end, is the hedonic question of pleasure that none of the others quite answers. Need, acceptance, preference, wanting, liking. The conventional bowl test observes the middle of that chain, acceptance and preference, and then quietly lets us infer rightward toward wanting and liking as though the steps were interchangeable. They are related. They are not synonyms, and the substitution of one for another is where a great deal of confidence has been manufactured. Later we will add a further construct the single meal cannot see at all, which is persistence, whether the animal still chooses the food after living with it, and that, it will turn out, is where the real disruption lies.

Movement III

THE DIET THE ANIMAL NEEDS MOST

If intake and liking come apart anywhere, they come apart most violently in the one place the stakes are highest, the sick animal and the diet meant to save it.

Consider the cat with chronic kidney disease. The therapeutic renal diet is one of the genuine achievements of veterinary nutrition. In the landmark trial, cats that ate one lived a median of 633 days against 264 for cats that did not, and that is not a marketing figure, it is survival. But the formulation problem here is unusually constrained. The nutrients most central to managing the disease, phosphorus above all, cannot simply be raised when they happen also to support sensory appeal, and the protein that carries much of a diet's phosphorus is moderated for the same clinical reason. Sodium is commonly kept low as well. None of this means palatability is impossible, and commercial renal diets are in fact engineered hard for acceptance. But it means the appeal has to be rebuilt inside a narrower nutritional envelope than an ordinary food enjoys, working around constraints an ordinary formulator never faces. The renal diet is, in large part by that necessity, among the harder foods in the category to make palatable. That is not an accident. It is the shape of the medicine.

Now feed it to the animal that needs it. The uraemic state that accompanies a failing kidney brings nausea and inappetence with it, and abnormal appetite is among the most commonly reported signs in these cats. So the very mechanism we have leaned on all along, the reliable hunger that empties a bowl and lets us read the emptiness as approval, is precisely the mechanism the disease takes away. The healthy dog at the fence may eat almost anything and hide the difference. The sick cat hides nothing, and will simply stop.

And the numbers from the clinic tell the story plainly. In that same survival trial, 21 of the 50 cats never reliably ate the diet at all, through limited intake or an owner unable to enforce the change. In a more recent survey of veterinarians, more than a third judged that the renal diet made up less than three-quarters of daily intake for most of their patients. On an intake sheet, a food that is mostly eaten reads as a formulation that mostly works. In the body of a cat quietly eating around it, it reads as a diet failing where it can least afford to, and a diet the animal refuses has, whatever the label promises, an efficacy it cannot deliver.

The healthy animal will eat to live and hide the difference. The sick animal hides nothing, and simply stops.

Intake is least trustworthy as a proxy for liking exactly where palatability matters most. Which leaves the clinician and the formulator holding an uncomfortable question. When the sick animal empties its bowl, or fails to, what have we measured, the food, or the disease?

We have been circling one half of the problem, the reading of the number, the way we let a gram of consumption stand for a measure of pleasure. Call that the interpretation problem, and it is real, and the sick cat shows how far it can go wrong. But over-reading the number is only the visible symptom, and beneath it sit two deeper faults that made the over-reading possible. We measure too little, because the test was built around what remains in the bowl rather than around the behaviour that emptied it. And we discard too much, because even the little we do capture is compressed, at the end, into a single figure. Three faults, then, stacked one on another. We measure too little, we discard too much, and we infer more than the measurement can support. The rest of this essay works down through those three layers, and then asks what we might build instead.

Movement IV

WHAT WE MEASURE

Begin with the measurement itself, because the first fault is built into the instrument. Return to the bowl. Before, 400 grams. After, 137. The animal consumed 263 grams, and what happened between the 400 and the 137 is very nearly everything we wanted to understand, and the protocol was designed to capture almost none of it. That is the quiet radicalism of the standard test. If palatability is a behavioural response that unfolds through time, why is the experiment built around what remains in the bowl at the end?

Think about what the animal actually did. How quickly it oriented to the food and approached it, whether it went straight to the bowl or hung back, how long it sniffed, how long between the first sniff and the first bite. Then, as it ate, how fast, in large bouts or small, accelerating or slowing. Whether it withdrew its head and came back, or switched bowls, and how often. Whether it lingered or bolted. When the meal ended, and, most telling of all, whether it came back. The two-bowl test enriches the picture by adding a choice, and first choice is a second genuine observation, but the architecture underneath stays the same. It is built around consumption as the endpoint. We kept the last number because a balance is cheap, robust and objective, while behaviour is messy, individuals differ, and scoring video by hand took forever. The field measured what it could measure well, and there is a quiet danger in that, because whenever the instrument defines the science, what is easy to measure slowly becomes what we believe the thing to be.

We built the experiment around what was left in the bowl, not around the animal that emptied it.

And what we left out has a shape, a timeline that a single endpoint erases. Aroma acts before the tongue arrives. Taste needs contact. Texture emerges during chewing. Fat contributes scent and mouthfeel and a chemistry that shifts as it warms. Hydrolysates release their amino acids and peptides once the food is sampled. Post-ingestive consequences arrive later still, some of them hours later. These cannot all be acting at the same instant, so no single final weight can tell us which of them mattered. Picture the sequence instead, detection to orientation to approach to first bite to sustained eating to return, and palatability stops looking like a number and starts looking like a process. Two foods can reach the same 65:35 ratio, one by seizing the nose and then losing the animal, the other by a slower approach and a longer, steadier meal. Those are not the same response. One captured the sniff. The other captured the meal. The bowl weight cannot tell them apart, and to the person trying to build the food, the difference is the entire job.

There is a whole dimension the endpoint cannot even reach, borrowed from a field that has studied it far longer. Behavioural science separates the motivation to obtain a reward from the pleasure of receiving it, wanting from liking, and shows the two can be pulled apart. We cannot ask a cat to rate its pleasure on a scale, and we should not pretend the human words map cleanly onto an animal. But the distinction reframes the whole enterprise. Instead of asking how much an animal ate when food was simply there, we can ask what it will do to get one food rather than another. Will it travel farther, wait longer, work harder, keep choosing that food as hunger fades and an easier option sits beside it. That question separates the need to eat from the wanting of this particular thing to eat, and it is far closer to what we meant by palatability all along. And notice what it does not give us. Even effort does not finally hand us liking. It hands us something different, and arguably richer, which is how strongly the animal is motivated to obtain the food, and the fact that our best new question still cannot reach pleasure directly is quietly fatal to the idea that there will ever be a single perfect palatability meter. The bowl never asked even this much, because the bowl was never designed to.

Movement V

WHAT WE DISCARD

Suppose, though, that the protocol never changed at all. Suppose we ran exactly the test we run today, the same bowls, the same 20 minutes, the same animals. There would still be a second fault, quite separate from the first, and in some ways more embarrassing, because it does not require any new experiment to see it. Even inside today's test, the animal generates far more information than we keep.

Imagine a two-bowl session that ends 65:35. Underneath that ratio, if anyone were recording it, is a sequence. At 3 seconds the animal orients to A. At 7 it sniffs A, at 11 it sniffs B, at 14 it returns to A, at 16 it takes the first bite, and eats without pause until it disengages near a minute, wanders to B, samples it briefly, then comes back to A and settles. A continuous weighing trace shows exactly how much went down in each bout. The final ratio, 65:35, is not the data. It is a single summary statistic sitting on top of a rich and largely discarded stream. We ran a behavioural film and kept one still frame from the end.

The intake ratio is not all the data. It is the one number we kept from a film we mostly threw away.

This is a different charge from the first, and worth keeping separate. The first fault is that the experiment was built too narrowly, around the endpoint. This one says that even within that narrow experiment, we collapse most of what we do observe. And this is the fault that technology is genuinely placed to fix, not by measuring more, but by keeping what the animal already shows us. A camera does not tire at the twentieth session. Computer vision can follow approach and orientation and the whole dance around the bowl. Load cells under the station turn two weighings into a continuous intake curve. Identity chips separate one animal from another automatically. Microphones can register patterns of crunching, chewing and pauses that the final weight never records. Researchers have even begun coding the faces of cats and dogs the way expression is read in pain and affective-state work, though it is early and no one should oversell a feline grimace. A word of precision matters here, because this territory is often described loosely. We are not reading an animal's mind or lighting up its brain. We are coding observable behaviour, the body and the face and the timing, and inferring a state from it, which is a far more modest and more honest claim. The behaviours the old test compressed, the sniff, the latency, the first bite, the bout structure, the return, are for the first time cheap to capture at scale.

But here is the discipline the whole essay turns on, and it is the most important sentence in it. More data is not more understanding. It would be the easiest thing in the world to bolt cameras and sensors and a machine-learning model onto the old test, generate a million measurements and learn nothing new. The question has to come first. What are we actually trying to know. Which behaviour carries information about it. Only then, which technology reads that behaviour reliably. Get that order wrong and we will have replaced an over-interpreted number with an over-engineered dashboard, and called it progress. Technology does not belong at the front of this story. It belongs in its proper place, between what we measure and what we understand, and never in the seat reserved for the animal.

Movement VI

BEYOND THE BOWL

So what would we build. Not, at first, a new machine, and not the abandonment of anything that works. The encouraging part is that the field has already begun to move, and much of what the next generation needs is here or arriving. A recent review of the field put it plainly: the one-bowl and two-bowl tests tell us how much is eaten but give little understanding of why the differences arise, and the newer work is turning toward behaviour, affective state and the analytical chemistry beneath. The upgrade comes in two stages, and the order matters.

The first stage keeps the established test exactly as it is, and instruments it. Keep the balance, keep the one bowl and the two bowls, so that decades of accumulated comparison are not thrown away, and simply stop discarding the rest of what the animal does in front of them. Add the continuous weighing, the vision, the individual identity, the timing of the feeding sequence. This is conservative, it is deployable now, and it costs the field none of its history. Its real value is not only the richer picture it gives. It is that it generates the evidence needed for the second stage, because only once we can see which behaviours actually carry information can we know what a better experiment should be built to capture.

The second stage is the genuine disruption. Having learned which parts of the feeding event mean something, redesign the experiment around the biology rather than around the convenience of the balance. Build protocols that deliberately separate attraction from acceptance, acceptance from preference, preference from motivation, and the single meal from the durable choice made after weeks of living with the food. That last is not a refinement. It is the whole commercial question, because the repeat purchase happens long after the panel has gone home, and a food can win a bright acute preference and lose the animal by the twentieth bowl.

This is also the point where artificial intelligence earns its place, and it is not the place it is usually given. The value is not a model that predicts a palatability score, which would only rebuild the old compression with more machinery. It is the fusion of streams that were never before brought together: the behaviour through time, the continuous intake, the identity of the animal, its previous exposures, and the measured chemistry and physics of the food. Bring those into one frame and we can stop asserting in advance what palatability is and let the data show us its structure. Perhaps there are foods that are high in attraction and poor in persistence, and others that are quiet at first and strong on return, and others that carry a hungry animal and collapse in a satiated one. Those categories should not be declared before the evidence exists. But an analysis that lets the dimensions emerge from the animal's own behaviour is a different enterprise from one that decides beforehand that everything must fold into a single word.

And here the old question itself begins to fail. We ask whether food A is more palatable than food B as though palatability were a single property, like moisture or protein, sitting in the food waiting to be measured. But suppose one food is thrilling at the nose, ordinary once eating begins and tiresome within a week, while another attracts less sharply, carries a meal beautifully and grows more preferred with familiarity. Which of them is more palatable. The honest answer is that the question has quietly folded several different biological phenomena into one word, and then asked a single number to carry all of them. The future is not a more accurate palatability score. It may be a palatability signature.

We have been asking which food is more palatable as though palatability were one thing. It may be several.

There is a second thing the old average hides, and it needs no new technology at all to see, only honesty about what a mean is. When a panel prefers A 60:40, that figure can mean most animals individually chose A in roughly that proportion, or it can mean half the animals strongly preferred A while half were indifferent or leaned the other way. The number on the report is identical while the underlying populations are entirely different. So the sharper question is not whether the panel preferred A. Did most animals prefer A, or did the average animal, which does not actually exist, prefer A? Once the identity chip and the camera let us follow the same animal across weeks, that question opens all the way up, and the interesting thing stops being that dogs preferred A 63:37, and becomes whether a given dog is consistent, whether one animal always responds to volatile attraction and another switches after 3 exposures, whether this cat approaches fast but ends meals early and that one refuses an unfamiliar food at first and comes to prefer it. The population mean washes all those trajectories together into a single ratio, and there is no average animal eating an average bowl beside the average owner buying the average bag. Longitudinal, individual phenotyping was economically impossible with a human scoring a panel by hand. It is not impossible now.

Tie those behaviours back to the chemistry and physics of the food, the volatiles associated with the approach, the lipid chemistry associated with sustained or declining engagement, the peptides that meet the tongue, the texture encountered during the chew, and the question stops being which palatant won and becomes why it won, when it won, and whether it will still win tomorrow. This is where the whole series converges. When a novel protein or a fermentation ingredient underperforms, the useful question is no longer simply whether the animal will eat it. It is where in the feeding sequence the unfamiliar ingredient does its damage. Does it dull the attraction, or is the attraction fine and the meal falls apart halfway through, or does the palatant rescue the first bite while the base formulation loses the animal by the twentieth. The Conversations on fats and plasma and hydrolysates were all, in the end, about single points along this sequence. A richer measurement is what lets us tell those points apart. There is a warning folded in, because a model trained on yesterday's ingredients may not understand tomorrow's proteins, and a fermentation product or a novel fat can sit outside the chemical space the model learned. The technology does not abolish the biology. It gives us another way to interrogate it, and the animal keeps the final vote.

Earlier I set out need, acceptance, preference, wanting and liking as a hierarchy, a ladder climbing from survival toward pleasure. Beyond the bowl, even that looks too neat. They behave less like rungs than like dimensions, interacting, sometimes moving together and sometimes pulling apart. An animal can want a food intensely and eat little of it because satiety has arrived, or accept a food for weeks without ever preferring it, or prefer one for its novelty and abandon it once the novelty is gone. Add attraction, meal engagement and persistence, and what we have been calling palatability stops looking like a score at all and starts looking like a signature. The essay began by finding a hierarchy hidden inside one loose word. It ends by finding that even the hierarchy was too simple.

I will not, in this essay, walk through how those signals are assembled into a working answer, because that assembly is the work itself, the point where the science stops being a public conversation and becomes someone's craft. The lighthouse can be described without handing over the map. But the thing the whole essay has been driving toward is simpler than any method. These signals are not unmeasurable. They are merely unmeasured by the standard test. The animal has been producing them all along, at every session, in plain view, and they disappeared not because they were invisible but because we were weighing the bowl.

None of which makes the bowl primitive. Sometimes the simplest measurement is the right one, and if I were launching a food tomorrow I would still want to know, plainly, whether animals eat it and whether they prefer it to what it replaces. But scientific maturity is knowing what a measurement cannot say. Intake is real, preference is real, first choice is real, and the danger begins only when we quietly enlarge them into something bigger than the behaviour we watched. The bones disappeared over the fence. The test food disappeared in the panel room. Both left the same evidence, an empty vessel and an animal that ate what was there, and the biology that emptied them was not necessarily the same. That difference, invisible on the balance, is the whole of it. A pet eats, in part, because life requires eating, and folded inside that necessity is everything else, attraction and choice and reward and persistence and learning, and something that in plain language we would call liking. For decades most of it vanished between the first weighing and the second. It did not vanish for the animal. It vanished for us.

So the question I would leave open is not whether the bowl was wrong. It was not. It is whether we are still willing, now that we can see so much more of the meal, to keep asking the animal only the one question the balance was built to answer. I do not think we should be. But that is a decision the industry has to make with its eyes open, and it has not yet, to my knowledge, even been put as a question.

We measure too little, we discard too much, and we infer more than the measurement can support.

The empty bowl has told us a great deal. It is time we found out what happened beyond it.

References

1. Aldrich, G.C. & Koppel, K. (2015). Pet food palatability evaluation: a review of standard assay techniques and interpretation of results with a primary focus on limitations. Animals 5(1):43-55. doi:10.3390/ani5010043

2. Tobie, C., Péron, F. & Larose, C. (2015). Assessing food preferences in dogs and cats: a review of the current methods. Animals 5(1):126-137. doi:10.3390/ani5010126

3. Calderón, L.A., Berendsen, B., Verbeek, E. & others (2024). Measuring palatability of pet food products: sensory components, evaluations, challenges, and opportunities. Journal of Food Science 89(9):5359-5382. doi:10.1111/1750-3841.17511

4. Elliott, J., Rawlings, J.M., Markwell, P.J. & Barber, P.J. (2000). Survival of cats with naturally occurring chronic renal failure: effect of dietary management. Journal of Small Animal Practice 41(6):235-242. doi:10.1111/j.1748-5827.2000.tb03932.x

5. Magalhães, T.R., Lourenço, A.L., Corbee, R.J. & Queiroga, F.L. (2023). Clinical management of feline chronic kidney disease in Portugal: a questionnaire-based study. Journal of Feline Medicine and Surgery 25(11):1098612X231206125. doi:10.1177/1098612X231206125

6. Berridge, K.C. & Robinson, T.E. (2016). Liking, wanting, and the incentive-sensitization theory of addiction. American Psychologist 71(8):670-679. doi:10.1037/amp0000059

Thursday, 8 October 2026

Would You Cook a Delicious Poison for Your Child?

THE UNWRITTEN ART

THE SAME GESTURE, A DIFFERENT BODY

THE PROJECTION

FEEDING WHAT YOU LOVE

References

About the Author

Thursday, 1 October 2026

A Cat Is Not a Big Dog: Why Petfood Palatability Is Species-Specific

SAME BOWL, DIFFERENT ANIMAL

THEY DO NOT TASTE THE SAME WORLD

THE PALATANT IS NOT THE MESSAGE

ONE FACTORY, TWO BOWLS

References

About the Author

Thursday, 24 September 2026

Petfood palatability in veterinary diets: what the patient will eat

THE COLOURS THE DISEASE REMOVED

FOUR WAYS TO BREAK THE AGREEMENT

MORE IS NOT THE ANSWER

THE FIRST MOUTHFUL

References

About the Author

Thursday, 17 September 2026

Petfood palatability: Why amount eaten under-measures liking

THE EMPTY BOWL

EATS TO LIVE

THE DIET THE ANIMAL NEEDS MOST

WHAT WE MEASURE

WHAT WE DISCARD

BEYOND THE BOWL

References

About the Author

Would You Cook a Delicious Poison for Your Child?