A long-term food is usually changed for a reason, often a health reason, which makes the first week a small trial that deserves evidence rather than impressions. What you watch spans meals, the litter tray, drinking and urination, the coat, and how lively the cat seems — six areas in all. None of them needs equipment, and together they answer the question the week is really asking — whether this food suits this cat — in terms a vet can act on. The transition itself is not yours to redesign: follow the plan already agreed, from your vet or from the label guidance, and let your role be the accurate recording and reporting of how the cat responds.
At the Bowl
Appetite at each meal is the first measure, so record it meal by meal rather than as a daily verdict. Note whether the bowl is finished, left half-eaten, or approached and abandoned, and whether the cat arrives keen, indifferent, or only eats when encouraged. Distinguish a cat that dislikes the new food's taste from one that wants to eat and cannot manage it, because those are different reports. A single skipped meal in a week of change is an observation; a cat that refuses the food outright, or eats less each day, is a deviation to report. Record treats, table scraps, and food taken from another pet's bowl too, since unrecorded extras quietly rewrite the trial you think you are running.
In the Litter Tray
Stool consistency and frequency give the clearest daily readout of how the gut is handling the change. Note how many stools a day, and describe them plainly: formed, soft, or liquid, and whether straining, mucus, or blood appears. Some softening early in a transition can reflect the speed of the changeover rather than the food itself, which is why the pattern across the week matters more than any single day. Stools that firm steadily tell one story; stools that worsen, or vomiting that joins them, tell another and belong in a phone call. Record vomiting separately and precisely — how often, when in relation to meals, and whether food, liquid, or foam comes up — because frequency and timing are what the vet will ask for first.
Water, Skin, and Energy
Water intake and urination are easy to overlook with a cat, so give them deliberate attention: note how fast the water bowl empties compared with the old routine, and whether litter clumps suggest the cat is urinating more, less, or straining. Skin and coat signs complete the picture, since food responses often show on the surface: watch for new scratching, over-grooming of the belly or legs, ear irritation, or a coat turning dull or flaky across the week. Energy is the summary measure — a cat playing, exploring, and keeping usual routines, or one going quiet and sleeping through former active times. None of these signs needs interpreting by you; each needs recording with the day it appeared, so the vet can line the surface signs up against the feeding days.
Reporting Deviations, Not Redesigning the Plan
The discipline of the week is to observe and report, not to improvise. If the stools loosen, the answer is not to invent a slower mixture or different quantities of your own; the transition follows the agreed plan, and deviations from the expected pattern go back to the vet who recommended the food, with your dated notes in hand. That conversation might adjust the plan, extend the changeover, or change the food entirely, and each of those decisions is properly the vet's. What you supply is the quality of the evidence: a week of dated meals, stools, vomiting, water, itch, and energy turns a vague report that the cat seems unsettled into a record the vet can judge in minutes.
KinsLe's Pet Passport holds the new food's start date, the agreed transition plan, and your daily observations together, building a health record that shows exactly how your cat settled on the diet.