Feeding by volume goes wrong because a cup of one kibble can hold twice the calories of a cup of another. Work from calories instead. Most adult cats need about 200 to 250 kcal a day, and the label tells you how to hit that number.
A lean 4 kg indoor cat that sleeps most of the day sits near the bottom of the range, around 200 kcal. The same cat with a cat tree it uses hard may move toward 250 kcal. A 5.5 kg cat needs more again, and a cat on a weight loss plan needs less than the bag suggests.
Vets often start from a resting energy estimate of roughly 60 to 70 kcal per kilogram of bodyweight raised to the power 0.75, then multiply for activity and neuter status. You do not need that formula at home. You need a kitchen scale, a note of the daily total, and a weekly weigh in.
Weight change is the real test. Feed a measured amount for two weeks, weigh the cat on the same scale at the same time of day, then shift the total by about 10 percent in the direction the number asks for.
Say the dry food label reads 380 kcal per 100 g. A 200 kcal target divides to about 53 g a day. Split that into two meals of roughly 26 g each, weighed, not poured by eye.
Now mix in wet food. If a 100 g tin holds 80 kcal, two tins give about 160 kcal, so add around 10 g of the same dry food, or a third of a tin more, to reach 200 kcal. Mixed feeding works, as long as both parts are counted.
An active cat of the same weight on wet food only might get three tins a day at that calorie density. The figure moves with the label, so check the tin you actually bought rather than the last brand.
Every complete cat food prints a calorie figure, usually as kcal per 100 g and often per cup or per tin as well. Typical dry cat foods run 350 to 450 kcal per 100 g. Typical wet foods run 60 to 110 kcal per 100 g because most of the tin is water.
Treats count. A single soft treat is often 2 to 5 kcal, so ten treats can be a tenth of the day. Keep treats under about 10 percent of daily calories and subtract them from the meals rather than adding them on top.
Weigh food. Scoop weights vary with kibble shape and how the bag settles, and a 20 percent error on 50 g is 10 g, which is around 40 kcal a day. That is enough to add close to a kilogram over a year on an indoor cat.
Cats cannot make enough of several nutrients themselves, including taurine, arginine, arachidonic acid and the active form of vitamin A. Those come from animal tissue, which is why a meat free diet needs careful formulation and why a dog diet is not a substitute.
Taurine deficiency damages the heart and the retina, and it has been documented in cats fed dog food or unsupplemented vegetarian diets. The result can be blindness and heart failure, and it is entirely preventable.
Look for wording on the pack that the food is complete for a life stage: kitten, adult or senior. That statement means it meets a nutrient profile standard for that stage. Keep raw fish to small occasional amounts, because an enzyme in raw fish destroys thiamine.
Kittens under six months need two to three times the calories per kilogram of an adult, spread over three or four meals. Pregnant and nursing queens need more again and are usually allowed free access to food while they raise the litter.
Senior cats often need fewer calories but better quality protein, since they digest fat and protein less efficiently. A sudden change in appetite, up or down, deserves a vet visit rather than a new brand.
Water matters as much as food. Cats have a weak thirst drive, and wet food is about 75 to 80 percent water, which supports urinary and kidney health. Several bowls, or a fountain, in spots away from the food encourages drinking.