Obesity occurs worldwide and unfortunately humans are not the only ones affected. Our beloved pets also suffer from weight problems. It’s estimated that 25% to 44% of dogs in the United States are overweight or obese and with an astounding 63% of cats being considered overweight or obese.

Causes of Obesity/Overweight

As in humans, calorie output must equal or exceed calorie input to maintain or lose weight. When the balance is shifted to the reverse, calorie input exceeds calorie output, weight is added to the body. As most dogs are considered companions vs working dogs (field trials, herders, walking/running partners, agility), they are prone to weight problems throughout their lives. Cats are even more prone to weight gain as often they are not involved in the activities mentioned above and can be difficult to motivate to exercise. While overeating is a major factor is in weight gain, this is not the only cause; there are several influences at play.

Signalment (breed, age, gender): certain breeds are more prone to weight gain than others. Labradors, Dachshunds, Shelties, Cocker Spaniels, Beagles, Basset Hounds, Cavalier King Charles Spaniels, and Carin Terriers have been shown to be predisposed to weight gain. As our companions age, adding weight is much easier than when they were younger; dogs over 2 years are at risk of obesity. Aging tends to slow down metabolic rate and decrease lean body mass. Aging is also associated with certain disease processes (arthritis) that can interfere with weight loss. Obesity tends to be seen more in females than males.

Food: pet diets have changed drastically over the years, mostly for the better. These changes have led to better tasting and better-quality diets. With better tasting food comes natural behaviors from our companions…begging for more food, treats, and overindulging at the bowl or feeder. Many treats now available also have high fat contents and/or are given in excess to recommendations. Competition for food within a multi-pet household can also lead to obesity. Access to table food contributes to obesity as well.

Lack of Exercise: this unfortunately, often parallels our sedentary lifestyle. It is recommended that our pets receive 30 to 45 minutes of aerobic exercise mixed with 1 to 2 hours of activity daily (this varies with breed, age, weight and outside temperature).

Surgical Alteration: spaying and neutering can lead to excess weight.

Metabolic Disorders: some medical conditions, such as hypothyroidism, can cause weight gain despite adequate caloric control.

Consequences and Complications of Obesity

Studies are showing that excess weight can have detrimental effects on our furry friends. The top 5 medical consequences are described below, along with a list of other complications.


Poor quality of and quantity of life – slimmer and leaner dogs were shown to live almost 2 years longer than their overweight counterparts. They also had a delayed onset of chronic illness; this means we may get to spend more years with companions if we maintain a healthy body weight. One study has also shown an improvement in the quality of our pet’s lives when they are leaner; they have increased energy, less emotional disturbances and overall decreased pain.

Osteoarthritis (OA) – known more commonly as arthritis. Frequently seen as discomfort/difficulty in getting up and down, struggling to climb stairs, shorter walks and play times or often described as “slowing down”, this can drastically influence daily living. Joints with OA are unhealthy joints and obesity contributes and exacerbates this unhealthiness. It is also speculated that being overweight can lead to an earlier onset to OA in some animals. Healthy weight acts as a preventative and treatment of arthritis; regularly the first step in alleviating pain and lameness associated with OA is weight loss.

Intervertebral Disc Disease (IVDD) – a painful medical condition where the cushioning disc between the back vertebrae start to bulge or herniate into the spinal cord space. Obesity can lead to unwanted additional stress on these discs or lead to the bulging of the disc. Dachshunds are the most represented breed with this condition, however any breed can be affected.

Subclinical Disease – these are diseases that are not yet evident and often undetectable visually but can be brought on by obesity. Often blood tests are needed to help diagnose these conditions.

Cardiopulmonary Effects – heart rates, ability to exercise, as well as breathing can all be affected by extra weight. Some conditions known to be linked to obesity are collapsing trachea and laryngeal paralysis; both of which can be eased with weight loss.


Diabetes Mellitus – this is one of the most strongly related medical conditions to obesity. There is a decrease in insulin sensitivity, meaning the body does not respond to high sugar levels in the body appropriately. Maintaining a healthy weight can be preventative and treatment for diabetes. In fact, weight loss the backbone of treatment for diabetic cats and increases the likelihood of achieving remission!

Urinary Disease – obesity may play a role in overall urinary health. Excess weight may lead bladder infections, inflammation, or stone formation. Weight loss with an active lifestyle can help prevent and treat some of these conditions.

Osteoarthritis – same as in the dog.

Subclinical Disease – obesity is suspected to predispose and aggravate diseases that are not yet evident in our pets.

Poor Quality and Quantity of Life – same as in the dog; leaner bodies help alleviate pain, lameness and help with longevity.

Other Conditions

Several other conditions known to be caused or complicated by obesity include but are not limited to:

  • Decreased or lowered immune system
  • Exercise and heat intolerance
  • Hypertension
  • Fertility or breeding difficulties
  • Increased risks of specific types of cancer
  • Skin infections
  • Increased difficulty performing surgery
  • Complications associated with anesthesia

Treating Obesity

Prevention is the best cure when it comes to our pets being overweight or obese. Because there are many approaches to weight loss, it is recommended that a weight loss program be initiated under the supervision of your veterinarian. With a thorough history on your pet’s nutrition, exercise and health status; a veterinarian can help tailor what will work best your individual dog or cat.

Sara N. Armon, DVM
Prescott Animal Hospital