Overweight, Obesity, and Pain in Dogs: 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 dogs?

More than 50% of dogs and cats 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 dogs’ lives.

What other medical conditions are associated with obesity?

Obesity dramatically increases the risk of diabetes mellitus, heart disease, and several types of cancer. The most recent scientific data reveals that carrying moderate excess weight shortens a dog’s life expectancy by as much as two years.

Being overweight or obese sets the stage for increased risk of joint damage, which can lead to osteoarthritis (OA) and chronic pain. At least 20% of all dogs, regardless of age, show some evidence of OA. The risk of OA goes up as an overweight dog gets older, and the risk increases in dogs with larger bone structure. So, the older and bigger an overweight dog is, the more likely it is to suffer from inflammation and pain associated with OA.

Dogs that are overweight or obese damage their joints over time and before anyone can see clinical evidence of the damage. It takes years of joint damage for changes from OA to show up on an X-ray.

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 dogs 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 dog 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 dog is overweight or obese?

The most reliable way to evaluate your dog’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 dog’s sides.
  • When viewing your dog from the side, the waist (between the rib cage and hips) should look “tucked up”. There should be no sagging belly or tummy.

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

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

To be sure about your dog’s body condition, ask your veterinarian for an evaluation. Your dog’s weight and body condition score will be recorded in your dog’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 dog can be treated and have his pain resolved.

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

Your veterinarian is an excellent resource for developing a weight-loss program for your dog. 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 dog’s individual needs.

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

If there is already evidence of OA, reducing inflammation and pain will help your dog become more active, which in turn will lead to weight loss. See the handout “Overweight, Obesity, and Pain in Dogs: Prevention and Action Plans” for more ideas to get your dog’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 dogs living in chronic pain. The path to successful weight loss includes a partnership between the dog 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 dog owner can shift to monitoring weight, while feeding to maintain lost weight and gradually increasing daily activity.

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