Feeding an overweight cat less food sounds simple, but a sudden cut can do more harm than good. Cats that lose weight too fast can develop a serious liver problem, so the safe route is always slow and steady. This planner builds a gradual plan that steps the daily portion down week by week, instead of dropping it all at once. You enter the current weight, the target weight, the number of weeks, and the energy content of the food. The tool then shows a weekly table in calories and in grams, so you can measure each meal with a kitchen scale.
The maths behind the plan starts with resting energy requirement, a standard veterinary formula. Resting energy is 70 times body weight in kilograms raised to the power of 0.75. For a 5 kilogram cat that works out at about 234 calories per day at rest. A normal adult cat needs roughly 1.2 times that figure for everyday maintenance, which is about 281 calories. The planner uses the current weight to set the starting amount and the target weight to set the finishing amount, then draws a straight line between them across the weeks you choose.
Why does the plan move in steps at all? Because a cat that is used to a large portion will notice a big cut at once, and begging, stealing food, and stress follow quickly. Small weekly steps are much easier to live with, for the cat and for you. A loss of around 1 percent of body weight per month is a sensible pace for most cats, and many vets suggest 1 to 2 percent per month as the safe range. If your cat is losing faster than that, the portion is probably too small and you should slow the plan down.
Here is a worked example. Take a 6 kilogram cat with a target of 5 kilograms, over 10 weeks, eating food with 350 calories per 100 grams. The starting amount is about 322 calories per day, or 92 grams. By week 5 the plan is near 301 calories, or 86 grams. By week 10 it reaches the target of 281 calories, or 80 grams. The change from week to week is only a few grams, which is exactly the point. Small steps keep the cat satisfied while the weight drifts down.
Measuring matters more than most people expect. A scoop or a cup can easily be 20 percent out, which wipes out the whole plan. Weigh the food in grams on a kitchen scale every day, at least until the new routine feels normal. Split the daily amount into two or three meals rather than leaving one big bowl down all day. Timed meals also make it easier to spot a change in appetite, which is one of the earliest signs that something is wrong.
Treats count too, and they are the usual reason a diet stalls. A few treats here and there can add 30 to 50 calories a day, which is a large share of a small cat allowance. Keep treats inside the daily total, not on top of it, and use part of the measured kibble as treats when you can. If other people in the house feed the cat, agree on one daily amount and one person in charge of it, or the plan will quietly fail.
Play helps, but it cannot fix a portion that is far too big. Short play sessions with a wand toy or a laser pointer, a few minutes several times a day, keep an indoor cat moving and burn a little extra energy. Climbing posts, boxes, and puzzle feeders add movement without adding food. Do not try to exercise a very overweight cat hard. Gentle, regular play is enough, and it also reduces the boredom eating that many indoor cats develop.
Weigh your cat every week, at the same time of day, on the same scale. Stand on a bathroom scale holding the cat, then subtract your own weight, or use a baby scale if you have one. Write the number down each week next to the planned amount. If the weight is flat for three weeks in a row, check the measuring, the treats, and any food the cat may be finding elsewhere, before cutting the portion further.
This tool is an educational estimator, not veterinary advice. Overweight cats can have health problems that change how they should be fed, such as diabetes, arthritis, or thyroid disease. If your cat is very overweight, loses weight suddenly, stops eating for more than a day, vomits often, or seems lethargic, talk to a vet promptly. A vet can confirm a safe target weight, because the ideal weight depends on frame size and breed, not on a single chart number.
The final point is patience. Weight that took a year to gain will not safely come off in a month, and that is normal. A steady loss of a few dozen grams per week, week after week, is a real result. Keep the routine simple, measure every meal, weigh every week, and let the table do the thinking. The planner gives you the numbers. Your job is only to follow them, one small step at a time.