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How much should I feed my cat? A vet answers

how much should i feed my cat
(Image credit: Getty Images)

When I tell a client their cat is overweight, “how much should I feed my cat, anyway?” is a question they often ask. Unfortunately, while that sounds like a pretty simple question, there isn’t an easy answer. Even when feeding them the best cat food, the quantity they need to eat in order to maintain a healthy weight can vary significantly, depending on genetic factors, your cat’s physical activity level, and the calorie density of your cat’s diet. Determining how much to feed your cat each day typically requires research, combined with some trial and error. 

Health risks associated with obesity in cats

The question, 'how much should I feed my cat?' has prompted numerous investigations. In a 2017 study, the Association for Pet Obesity Prevention found that 59.5% of cats in the United States are classified as overweight or obese.This isn’t purely a cosmetic problem; carrying excess weight is known to shorten a cat’s lifespan. Obese cats are at higher risk of a number of serious medical conditions, including diabetes mellitus, osteoarthritis, bladder stones, and skin and bladder infections (caused by decreased self-grooming).

While many of the risks associated with obesity are slow to develop, obese cats are also prone to an acute illness called hepatic lipidosis or fatty liver disease. Hepatic lipidosis can develop within a matter of days, in an obese cat that appears otherwise healthy. When an obese cat goes just three to four days without eating, the body’s fat stores are rapidly mobilized for energy. This fat floods the liver, interfering with normal liver function. Affected cats develop icterus or jaundice (yellow color of the eyes and gums), and often develop vomiting and diarrhea. If not treated quickly and aggressively, hepatic lipidosis can be fatal. 

Given the health risks associated with obesity, all cats should be maintained at a healthy body weight. If your cat is obese, however, it’s important to work with your veterinarian to develop an appropriate weight-loss plan. Don’t start your cat on a crash diet without veterinary guidance, because a sudden reduction in calories may be enough to trigger hepatic lipidosis in some obese cats. 

Dry vs canned food: Which is best? 

Before determining how much to feed, you need to decide whether to feed your cat dry cat food or the wet cat food. Most veterinarians feel that cats benefit from a wet diet, because these diets are often lower in carbohydrates than dry food. 

Additionally, the best wet cat food provides additional water intake for cats; many cats drink limited amounts of water, and dehydration can play a role in the development of chronic kidney disease and lower urinary tract disease (buying a pet water fountain can also encourage drinking). However, despite these suspected benefits of wet food, there have been limited studies comparing the real-world impacts of dry vs. wet diets. Therefore, it’s difficult to definitively determine whether wet food is better for cats than dry food. 

While wet foods may have their benefits, they also have their drawbacks. Wet food may be more expensive to feed than the best dry cat foods. Additionally, wet food cannot be left at room temperature in your cat’s bowl; anything that is not eaten within a couple of hours must be discarded. Feeding wet food also typically requires storing partial cans – covered – in the refrigerator. While these may all be relatively mild inconveniences, these inconveniences lead some cat owners to prefer dry food over canned food. 

If you’re unsure of whether to feed your cat dry or canned food, talk to your veterinarian. They are familiar with your cat’s health history and can help you make the most appropriate decision for your cat. 

Use label feeding guidelines as a starting point 

Once you have decided which cat food to feed your cat, you will need to determine how much to feed your cat each day. Each cat food has different feeding guidelines, because foods differ in caloric density. On the label of any can or bag of cat food, you will see a chart that provides recommended daily feeding guidelines, based on body weight. This daily food intake should be divided into two or three identically-sized meals. Keep in mind, however, that feeding guidelines are not exact. The laboratory cats that are involved in feeding studies are often far more active than the average house cat. Additionally, every cat has a slightly different metabolism. 

When you measure out your cat’s food, accuracy is important. Dry food should be measured using a measuring cup; don’t try to 'eyeball' it, because a small increase in food can translate to a large increase in calories! Wet food is often measured as whole or partial cans, which makes measurement a little more straightforward.

how much should I feed my cat

(Image credit: Getty Images)

Monitor your cat’s body condition and make changes as needed

Because every cat’s metabolism differs, some cats may need more or less food than the label guidelines recommend. Therefore, you should monitor your cat’s body condition to ensure that they are not becoming overweight or underweight. A cat that is at a healthy weight will have an obvious waist when viewed from the side or from above. Additionally, you should be able to easily feel your cat’s ribs, but not be able to see them. If you’re concerned that your cat is getting overweight, read our guide to healthy weight loss for cats.

Give your cat several weeks to adjust after any food change, then re-evaluate your cat’s body condition. If your cat is gaining weight, decrease her daily food intake by approximately 10%. If your cat is losing weight, increase her food quantity by 10%. Continue making these small changes every few weeks until you arrive at a food quantity that allows your cat to maintain a healthy weight. 

Weight management will keep your cat healthy

The question, 'how much should I feed my cat?' is usually asked in the context of weight management. It’s relatively uncommon for a pet cat to be underweight, but overweight cats are a common occurrence. By following label recommendations, measuring your cat’s meals, and monitoring your cat’s body condition closely, you can ensure that your cat remains at a healthy body weight, and avoids the negative impacts associated with obesity. 

Catherine Barnette DVM

Dr. Barnette received both her Bachelor of Science degree in zoology and her Doctor of Veterinary Medicine from the University of Florida. She’s an experienced writer, educator, and veterinarian, with a passion for making scientific and medical information accessible to public and professional audiences.