Think You Have a Fat Cat? The Ten Things You Need to Know

Overweight cat
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1. What should a cat weigh?

Though most cats should be about 7-12 lbs, the ideal weight for an individual cat depends on the size of the cat’s frame, so we focus on body condition score rather than just weight. We use a body condition scoring system to help us determine the amount of body fat an animal has. There are a few different scales, but all are based on the amount of fat over a pet’s ribcage. For dogs and cats, if you feel over the pet’s rib cage, it should feel no more padded than the back of the owner’s hand. (See the Muscle Condition Score chart: Cats or Dogs) Your cat is overweight if he is 10% more than the ideal weight and obese if over 20% of the ideal weight.

2. What are the risk factors for obesity in cats?

One study showed overweight cats were more likely to be neutered and male. Being overweight was also associated with diseases like diabetes, cancer, and skin problems. Indoor cats and those that are less active are also more likely to be overweight. While dry foods and diets that have more carbohydrates are often blamed for cats becoming overweight, several studies have shown that this is not true and that calorie intake is more important than the type of food.

3. If I spay or neuter my cat, will it cause them to gain weight?

It’s been shown that cats are more likely to become overweight after spaying or neutering. We routinely recommend to decrease the amount of food after this procedure by 20-30% and to watch body condition closely, but it’s still important to keep your kitten on a diet that meets the needs of growing cats until he is at least 1 year of age.

4. Why does it matter if my cat is overweight?

Feline obesity has been associated with many diseases including diabetes, skin disease, and arthritis/joint pain. While you might not see any problems, overweight pets have more risks if they need anesthesia and higher medical costs. Additionally, studies have shown that being overweight increases inflammation throughout the body and we are just learning about a large number of health problems that can be associated with chronic inflammation.

5. Should I see my veterinarian before starting a weight loss plan?

Before you start your cat on a weight loss plan, you should have a discussion with your veterinarian. The veterinarian will determine your cat’s optimal weight, test for medical issues predisposing him to obesity, and assess overall health with blood and urine testing.

6. Are high-protein weight-loss diets ok for cats?

Most commercial diets designed for weight loss in cats are high in protein to compensate for the fact that the cat will be eating few calories. However, each cat is an individual, so your veterinarian will assess your cat and likely perform health screenings such as bloodwork to determine the level of protein and other nutrients that are most appropriate for your cat.

7. What are the factors that make a weight loss plan successful?

The keys to success are working as a team with your family and your veterinarian and being flexible. Every pet has different nutritional needs, so we need to assess each as an individual and consider the program as a whole. Helpful tips include keeping track of all the forms of food your cat gets, weighing your cat frequently with an infant scale (buying your own will make life for you and your cat much simpler!), and being very precise measuring the amount of food being given (many owners like to use a gram scale at home as measuring cups can be tricky to get exact).

8. If my cat is an indoor cat, how do I make sure they get enough exercise?

We have to get creative and ensure cats are enjoying their physical activity or they won’t do it! Spreading the food throughout the house, using food dispensing toys or even using laser lights can be examples of ways to increase activity. We have a client who opens up a can of cat food and her cat follows her around the house for 5-10 minutes for exercise before each meal! Additionally, there is an excellent website by Ohio State University that helps owners increase environmental enrichment for pets:

9. My cat grazes throughout the day, is that ok?

Feeding unlimited amounts throughout the day is challenging because we don’t know how many calories the cat is eating. Unfortunately, there is no food that every cat can eat as much as they want and still lose weight. A way to start to address this issue is to measure the amount of food your cat eats in a day to determine how many calories he is eating (measure how much food you put out in the morning and see how much is left the next morning). This information will be extremely helpful to your veterinarian in designing a safe and effective weight loss program for your cat.  Measured amounts of dry food put out throughout the day can be an effective way to mimic your cat’s grazing patterns. This can be a big challenge when you have more than one cat. It will be necessary to feed your cats separately if one or more of them need to lose weight. There are lots of new electronic feeders that can make easy work of multiple small meals and feeding multiple cats.

10. Where should cat owners start?

  • Have your veterinarian assess your cat’s weight and body condition score and talk with them about any concerns you may have. You should start thinking about maintaining a healthy body weight from that first kitten visit!
  • Tell your veterinarian about the exact diet you’re feeding (the brand, product, and flavor). It’s also important to list any treats, table food, and foods used to administer medication. Your vet can then help you calculate exactly how many calories your cat is receiving.
  • Reduce calories by 20-30% at the time of spay/neuter when energy requirements decrease (but don’t change to adult food until at least one year of age).
  • Try to prevent your cat from becoming overweight, but if he puts on a pound or two, be sure to address it quickly before your cat gets even heavier. It’s much easier for your cat to lose a small amount of weight before it becomes overwhelming.
  • If your initial effort at weight loss is not successful or your cat has other medical conditions, consider consulting with a veterinary nutritionist (

Posts authored by the Clinical Nutrition Service team are by Dr. Lisa M. Freeman, DVM, PhD, DACVN, Dr. Deborah E. Linder, DVM, MS, DACVN, and Dr. Cailin R. Heinze, VMD, MS, DACVN

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