How many calories does a cat need to lose weight? As a starting point, about 1.0 times its resting energy requirement (RER) — less than the 1.2 times RER that a typical neutered adult cat needs to hold its weight, but not a crash diet. This guide is the full calorie table for weight loss: the daily calories, cups, and grams for a cat at every weight, how to use the table, how fast weight should come off, and what to do when the weight stops falling. Every figure is an estimate, and a cat that needs to lose a lot of weight should have a plan set with its vet.
The short version is: find your cat's weight in the table, feed the weight-loss calories for that row, measure every gram, keep treats under 10% of daily calories, and aim for about half a percent to 1% of body weight per month. Weigh monthly, and if weight is not moving after a month, cut food by about 10% and re-weigh in another month. The cat calorie calculator works out the same figures for any weight, and the how to help a cat lose weight safely guide gives the full plan around the numbers.
How many calories to lose weight for cats
Start with the resting energy requirement, or RER — the calories a cat burns at rest. The formula vets use is: RER equals 70 times body weight in kg to the power of 0.75. A typical neutered adult cat needs about 1.2 times its RER to hold its weight, and a cat that needs to lose weight usually needs about 1.0 times its RER as a starting point. The table below gives the daily calories for a cat at different weights, at the normal adult factor, at the weight-loss target, and in cups and grams of a typical dry food at 350 kcal per cup.
| Body weight | Normal adult calories | Weight-loss calories (target) | Cups / grams of dry food per day |
|---|---|---|---|
| 2 kg | 140 | 120 | 0.3 cups / 34 g |
| 3 kg | 190 | 160 | 0.5 cups / 46 g |
| 4 kg | 240 | 200 | 0.6 cups / 57 g |
| 5 kg | 280 | 235 | 0.7 cups / 67 g |
| 6 kg | 320 | 270 | 0.8 cups / 77 g |
| 7 kg | 360 | 300 | 0.9 cups / 86 g |
If your cat is between two rows, take the lower figure first: it is easier to add food to a cat that is losing weight too fast than to take weight off a cat that has gained it. Note that calories are the real target and cups are only a translation: different foods have very different calorie densities, so always check the kcal per cup or per 100 g on your own bag or tin and work from that. The cups and grams figures above assume a typical dry food at around 350 kcal per cup — a common figure, but your food may differ, and the bag's number always wins over this guide's.
How fast should a cat lose weight?
Slowly. A commonly cited safe target is about half a percent to 1% of body weight per month, which means a 20 kg dog losing about 200 g a month and a 5 kg cat losing about 25 to 50 g a month. That sounds slow, and it is — but slow weight loss is the kind that stays off, because it gives the cat time to adjust, keeps muscle, and does not leave the cat hungry and miserable. A cat that loses weight faster than that is losing muscle as well as fat, and a cat that loses weight fast can develop a serious liver problem called hepatic lipidosis, which is a veterinary emergency. If your cat is losing weight faster than the target, feed a little more and mention it to your vet.
Weigh the cat monthly, at the same time of day, on the same scales, and write the number down — the line over months is what matters, not any single reading. Feel the ribs at every weigh-in too: you should be able to feel them easily under a thin layer of fat, and see a waist from above and from the side. A cat that is losing weight but still has no waist is still overweight, and a cat whose ribs are easy to see and whose waist is very obvious may have gone too far. The how to weigh your cat at home guide explains the bathroom-scale method, and the cat body condition score chart shows the nine-point scale vets use.
Turning calories into food
Once you have the calorie target from the table, turn it into food using the kcal figure on your own bag or tin. Divide the daily calories by the kcal per 100 g, and multiply by 100, to get grams per day; divide the daily calories by the kcal per cup to get cups per day. A cat that needs 200 calories a day and eats a dry food at 350 kcal per cup needs about 0.6 cups, or about 57 g, a day. Split that amount into two meals a day for an adult cat — morning and evening — rather than one large meal, because two smaller meals are easier on digestion and keep the cat feeling fed through the day.
Measure food with scales or a measuring cup, not a mug or a handful: a mug of dry food can carry a quarter more calories than a measured cup, and that quarter is often the whole difference between losing weight and not losing it. Keep treats under 10% of daily calories, and count them — use the cat's own food as treats, or a single low-calorie treat. If you feed wet food, use the tin's kcal figure to convert: a typical wet food is around 70 to 100 kcal per 100 g. Mixed feeding is fine as long as the total calories add up. The cat food calculator converts calories into cups and grams for any food, and the cat feeding chart by weight guide gives the daily amounts by weight.
When the weight stops falling
Weight loss is rarely a straight line, and a month with no change is normal — it is a plateau, not a failure. When a plateau happens, cut food by about 10% and keep going for another month, rather than abandoning the plan. If weight still does not move after two months, or if the cat is lethargic or off its food, see a vet. A plateau can also happen because the cat is now lighter and burns fewer calories than it did at the start — a lighter cat needs less food, so the target that worked at the start may need cutting again as the cat loses weight. Re-check the table with the cat's new weight every month, and adjust the amount to the new row.
Do not cut food by a large amount at once, and do not change food every few weeks: a weight-loss plan needs at least two months before it can be judged, and a food changed after two weeks has not had a fair trial. Do not forget treats: treats, table scraps, and food from other pets' bowls all count, and they often add up to more than the meal itself. If there are children in the house, agree together who feeds the cat and what treats are allowed, because a cat fed by three people is fed three times. The cat weight loss diet plan guide covers plateaus in full, and the best exercise for overweight cats guide gives a safe build-up plan for exercise.
Keeping the weight off
Once the target is reached, do not go back to the old amount: a cat that has lost weight needs less food than it did before, because a lighter cat burns fewer calories. Work out the new maintenance amount from the table, using the cat's new weight and the normal adult factor, and keep the food measured, the treats under 10% of daily calories, and the exercise daily. Keep weighing monthly for life: a cat that is weighed monthly and fed a measured amount will hold its weight, and a cat that goes back to food by eye will put the weight straight back on.
A cat that has lost weight and kept it off for six months has succeeded — and it is worth celebrating, because most weight-loss plans fail at the maintenance stage, not the loss stage. Keep the routine that worked: measured food, two meals a day, treats counted, exercise daily, and a monthly weigh-in. If the weight starts creeping up again, cut food by about 10% and re-weigh in a month, before it becomes a problem. The obesity in cats guide covers the health risks of putting the weight back on, and the cat ideal weight calculator works out a target weight range for life.
For related reading, see the cat calorie calculator, the how to help a cat lose weight safely guide, the cat weight loss diet plan guide, the cat food calculator, the best exercise for overweight cats guide, the cat body condition score chart.
Frequently asked questions
How many calories does a cat need to lose weight?
As a starting point, about 1.0 times its resting energy requirement (RER), where RER equals 70 times body weight in kg to the power of 0.75. A cat of 4 kg needs about 200 calories a day to lose weight, against about 240 at normal maintenance. Use the table above for your cat's weight, and adjust by monthly weigh-ins.
How fast should my cat lose weight?
A commonly cited safe target is about half a percent to 1% of body weight per month. That sounds slow, and it is — but slow weight loss is the kind that stays off, and fast weight loss loses muscle as well as fat. In cats, rapid weight loss can cause a serious liver problem, so slow is especially important for cats.
How do I turn calories into cups or grams?
Divide the daily calories by the kcal per cup on your bag to get cups per day, or divide by the kcal per 100 g and multiply by 100 to get grams per day. A cat that needs 200 calories a day and eats a dry food at 350 kcal per cup needs about 0.6 cups, or about 57 g, a day. Always check your own bag's number — it wins over this guide's.
What if my cat's weight stops falling?
A plateau is normal — weight loss is rarely a straight line. Cut food by about 10% and keep going for another month. If weight still does not move after two months, or if the cat is lethargic or off its food, see a vet. Re-check the table with the cat's new weight every month, because a lighter cat burns fewer calories.
Do treats count when losing weight?
Yes — treats, table scraps, and food from other pets' bowls all count, and they often add up to more than the meal itself. Keep treats under 10% of daily calories, use the cat's own food as treats or a single low-calorie treat, and agree in the household who feeds the cat.
How do I keep the weight off once it is lost?
Do not go back to the old amount: a cat that has lost weight needs less food than it did before, because a lighter cat burns fewer calories. Keep the food measured, keep treats under 10% of daily calories, keep exercise daily, and keep weighing monthly for life.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.