Why memory alone cannot answer this question
Owners understandably blur two very different events: a cat who dislikes a food and a cat whose body objects to it. Memory makes the blur worse, because a dramatic vomiting episode sticks while three calm days on the same food fade, and a refused bowl gets retold as the food making her ill. A written diary, kept briefly and precisely, replaces impressions with a sequence your vet can actually use. It does not diagnose anything by itself, and that restraint matters: the diary’s job is to produce a trustworthy pattern, not a verdict, because true food intolerance and allergy in cats are less common than preference, hairballs, stress, and unrelated illness, all of which a diary also helps to reveal.
Decide the question before you start. You are testing one suspicion at a time, for example whether a particular protein or a new food coincides with loose stools, not auditing her entire diet at once.
What to write down, every day, in the same way
Record the food’s exact identity, the amount offered and the amount actually eaten, and the time of each meal. Against that, note stool consistency and frequency, any vomiting and how long after eating it occurred, scratching or head shaking, ear condition, sneezing or watery eyes, and her general energy and appetite.
Mark stools simply as formed, soft, or liquid, and note treats and household changes on the same line, because an unrecorded treat can look like a reaction to the dinner you were testing. One change at a time is the rule that gives the diary its power. Introduce the test food, hold everything else steady for a sustained period, and resist the urge to add a probiotic, swap the litter, and change the food in the same week. If signs appear, withdraw the food and record whether and how quickly they settle; if they settle, a later cautious re-exposure, ideally discussed with your vet, is what separates coincidence from pattern. A single bad day proves nothing in a species that produces hairballs and the occasional empty-stomach vomit on any diet.
Reading preference in the diary
Preference writes a recognisable signature. The cat sniffs, may taste, and walks away untroubled; she eats a known favourite with enthusiasm soon afterwards; her stools, skin, and energy stay normal throughout; and the refusal is specific to a flavour, texture, or temperature rather than to eating itself. Those are negotiating positions, not symptoms, and the correct response is to choose a complete food in a format she likes rather than to keep testing her with variations of one she has clearly voted against.
Intolerance, by contrast, repeats physically. The same food is followed, across more than one exposure, by loose stools or diarrhoea, vomiting beyond the occasional hairball, excess gas, or itchy skin and recurrent ear trouble, and the signs fade during the period off the food.
Turning the diary into a vet-ready record
Keep the diary for a defined stretch and then review it whole, marking the days signs occurred against the foods eaten in the preceding meals. Bring that marked timeline to your appointment; it can save weeks of guesswork and may shape whether the vet suggests a formal elimination diet, which is stricter than home testing and the reliable route when a genuine food reaction is suspected. Stop home experiments and book promptly if you see blood in stools or vomit, repeated vomiting, refusal of all food for more than a day, weight loss, or a kitten with diarrhoea, since those need care, not data collection.
Kept alongside vaccinations and weight notes, the diary becomes part of her health story rather than a loose sheet, and KinsLe Pet Passport holds those food trials, reactions, and vet findings together in one packet you can hand over at any appointment.