Obesity Poses Serious Health Hazards to Pets

September 1, 2015

In Canada's Pet Wellness Report (published in 2011), Canadian veterinarians identified weight control/management as the number one thing a pet owner can do to increase the length of their pet’s life. There are two ways a pet can be excessive in weight. Using a standard scoring system with 9 points, where 1 is emaciated/thin and 9 is morbidly obese, a pet is defined as overweight when scoring 6-7/9 and is obese when scoring >7/9 on the scale. Caregivers need to understand that there are serious health risks involved for obese pets, in fact, the list of harmful effects of obesity on pets is a long one.

  • Overweight dogs don't live as long as lean fit healthy pets do. A study released in 2001 by pet food manufacturer Purina found average life span in the Labrador Retrievers kept lean through their life (by feeding 75% of the control group diet amounts) exceeded that of control dogs by 1.8 years or a 15% longer life! The study lasted 14 years, and also found delayed onset of many chronic conditions we see in older pets.
  • Diagnosis of health disorders is more difficult in obese pets, because it is more difficult to auscultate (listen with stethoscope) efficiently, or palpate (feel the abdomen or other structures), or to get proper samples (for example, venipuncture, or vein access may be more difficult). 
  • Obese pets are at a greater risk during anaesthesia and surgery since they have reduced lung function, sometimes decreased liver and kidney function, greater risk of wound infection and require more anaesthetic than healthy weight pets. The surgeon may also be challenged due to excessive body cavity fat stores, as internal structures may be embedded deeply in these fatty accumulations. 
  • High blood pressure (hypertension) may develop; increases the risk of kidney, heart and vascular (blood vessel) diseases.
  • Obese pets have an increased incidence of arthritis (degenerative joint disease), and spinal disc problems compared to healthy weight pets. Obese pets also have more problems moving about (known as reduced mobility) than their thinner counterparts.
  • Obese pets tend to play and exercise less, and if exercise is vigourous pets are more likely to develop torn knee ligaments (known as “cranial cruciate rupture”); obesity leads to impaired endurance during exercise, increased fatigue. 
  • Obese pets tend to be less able to fight off infectious diseases and may have slower healing. 
  • Because of the insulating properties of fat, obese pets are less able to endure hot weather, and may become more irritable or require enhanced cooling strategies to avoid overheating (hyperthermia).
  • The prevalence of skin problems is 40 per cent higher in overweight dogs than dogs at optimum body weight.
  • Breathing problems may be significant if breeds of pets with very short nose/skull conformation (known as brachycephalic) become overweight as the fat presses in on the airways, and heat or exercise both may further compromise the system in these obese pets.
  • Pets that are obese have an increased risk and severity of diabetes mellitus. A complex interplay with insulin metabolism and other metabolic processes due to release of hormonal factors from the fat tissue lead to interference with normal hormonal balance in the pet.
  • Reduced reproductive success
  • Gastrointestinal problems are over-represented in obese pets, have increased constipation, flatulence.
  • Slightly increased cancer rate in obese pets has been proposed. A 2007 American Journal of Veterinary Research report of large numbers (14,670 with and without cancer dogs), with different types of cancers found higher or lower rates depending on the type of cancer.
  • Liver function may be changed due to the accumulation of fat in the liver, for example, obese cats with sudden reduction in food intake or other health issues may develop fatty liver (hepatic lipidosis), a life-threatening condition.

All these effects contribute to a reduced life span and negatively affect the quality of a pet's life. Pets that are healthy and physically fit tend to live longer, are happier and enjoy life more. Talk with your veterinarian to find out how you can keep your pet physically fit and a healthy weight/body condition score.

(Revised August 2015)