Overweight, Obesity, and Pain in Cats: Overview

By Canadian Academy of Veterinary Nutrition (CAVN), Sarah K. Abood, DVM, PhD; Krista Williams, BSc, DVM; Robin Downing, DVM, CVPP, CCRP, DAAPM

Is being overweight or obese really a problem for cats?

More than 50% of cats and dogs in North America are overweight or obese. These epidemic levels are reflected in the human population as well. Obesity in pets is now the most important disease process pet owners must face. The negative or detrimental effects of obesity are far-reaching, because it contributes to other diseases and shortens cats’ lives.

What other medical conditions are associated with obesity?

For overweight and obese cats, one major concern is the dramatically increased risk of diabetes mellitus. In addition, obesity increases the risk of heart disease and many types of cancer. Although there is not yet a scientific study in cats, excess weight and obesity in dogs has been shown to shorten life expectancy by as much as two years. There is no reason to expect that the situation is different for cats.

Being overweight or obese sets the stage for increased risk of joint damage, which can lead to osteoarthritis (OA) and chronic pain. One study showed that 90% of cats 10 years and older had X-rays with significant deterioration of multiple joints - in both the legs and spine. It takes years of joint damage for such changes to show up on an X-ray. That means cats that are overweight or obese are traumatizing their joints for a long time before clinical evidence of that damage is found.

Is there more to this linkage between obesity and pain?

Until recently, veterinarians thought that the increased pain and inflammation associated with OA in overweight and obese cats was primarily due to increased wear and tear on the joints. We now know fat tissue is biologically active, and it secretes hormones and other chemicals that cause inflammation. Fat cells produce a hormone called leptin, which causes inflammation when it enters joints. Leptin may also influence bone changes associated with OA.

In addition, inflammation can affect the body’s responses to other hormones, such as cortisol and insulin, further unbalancing the body’s attempts at self-regulation and influencing the amount and extent of pain a cat may experience.

The important underlying message is that fat itself contributes to inflammation, inflammation is a part of the pain associated with OA and degenerative joint disease, and being overweight or obese contributes to this vicious cycle.

How can I tell if my cat is overweight or obese?

The most reliable way to evaluate your cat’s body condition is with a hands-on examination. There are three key areas of the body to evaluate:

  • Just behind the shoulder blades, you should be able to feel individual ribs easily with the flats of your fingers.
  • At the end of the rib cage, where the lower back begins, you should feel a clear indentation – like the shape of an hourglass - on each of your cat’s sides.
  • Although some cats have a fold of skin that droops between the rear legs, the waist (between the rib cage and hips) should feel “tucked up”.

If all these criteria are met, odds are strong that your cat is in good body condition, which can directly contribute to a pain-free lifestyle.

I’m not sure if my cat is overweight or obese. How can I be sure?

To be sure about your cat’s body condition, ask your veterinarian for an evaluation. They will record your cat’s weight and body condition score in your cat’s medical record as a baseline (starting point). Be sure to ask that a pain assessment be included in the exam. The earlier pain is detected, the quicker your cat can be treated and have her pain resolved.

I know my cat is overweight. What can I do?

Your veterinarian is an excellent resource for developing a weight-loss program for your cat. They will recommend a specific food and portion per day and provide guidance about  how to deliver that portion based on lifestyle, convenience, and your cat’s individual needs.

"Your veterinarian is an excellent resource for developing a weight-loss program for your cat."

If there is already evidence of OA, reducing inflammation and pain will help your cat become more active, which in turn will lead to weight loss. See the handout “Overweight, Obesity, and Pain in Cats: Prevention and Action Plans” for more ideas to get your cat’s weight and body condition score to an ideal level for the highest quality of life.

What is the take-home message?

Fat cells contribute to inflammation. Inflammation causes pain. Therefore, carrying extra fat cells contributes to cats living in chronic pain. The path to successful weight loss includes a partnership between the cat owner and their family veterinarian. Together, they must collaborate to set goals, monitor pain management strategies, and track results over time.

Regular weigh-ins and body condition checks will be necessary to determine when or how to adjust food portions or diets. Once an appropriate weight or body condition score has been reached, the veterinarian and cat owner can shift to monitoring weight, while feeding to maintain lost weight and gradually increasing daily activity.

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