Obesity: A weighty problem in pets?

Updated: Dec 13, 2021

Obesity and Overweight - What is the difference?


Obesity refers to an excessive accumulation of body fat with an average Body Condition Score (BCS) > 4.5 on the scale of 1 to 5 and overweight refers to dogs and cats having an average Body Condition Score (BCS) > 3.5 and < 4.5. Naturally, dogs and cats in the wild regulate their body fat by the amount of food they consume. In the modern domesticated pet, like for the modern man, they tend to eat better food and exercise less often than their forerunners, hence the risk of them becoming overweight and obese.

Body Condition Score Chart
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How common is obesity in pets?


Recently, research has shown that 34.1% of dogs are overweight or obese (29.0% overweight, 5.1% obese) and this is most common in middle-aged dogs (around 6 to 10 years of age), neutered males and spayed females. Uncastrated males had the lowest occurrence of overweight and obesity.

Excess body weight is one of the most common medical diseases of dogs and cats. Overweight animals weigh 10 - 19% greater than their optimal body weight, while obese animals weigh 20% more than their optimal body weight.

In cats, it is estimated that approximately 20-52% of cats are overweight to grossly obese. The prevalence of obesity in cats is greatest in young-to-middle age cats, which declines in senior populations (ie after 9 years of age). Overweight and obesity is due to the accumulation of adipose tissue (fat), consistently due to excess calorie intake of individual animals' requirements.

What predisposes pets to obesity and overweight?


There are three factors that predispose dogs or cats to obesity and overweight. There are:-

  1. Age: In juveniles, this is as a result of them being fed ad-libitum ie, the food is available at all times. With increasing age, the prevalence of obesity is greatest in middle age (6-10 years).

  2. Gender: Neutered dogs have the highest prevalence with the lowest prevalence in intact males.

  3. Breed (Genetics): Certain breeds are more prone to overweight and obesity than others.

  4. Dog breeds that are predisposed to weight gaining:-

  5. Cavalier King Charles Spaniel

  6. English Cocker Spaniel.

  7. Labrador Retriever

  8. Dalmatian

  9. Dachshund

  10. Rottweiler

  11. Golden Retriever

  12. Shetland Sheepdog

  13. Mixed-breeds.

  14. Cat breeds predisposed to weight gaining:-

  15. Maine Coon,

  16. Norwegian Forest Cat

  17. Himalayan

  18. Neva Masquerade,

  19. Cornish Rex

  20. British Shorthair

  21. Ragamuffin

  22. Chausie

  23. Siberian

  24. Savannah

  25. Domestic Shorthair

  26. Lifestyle (Behavioural disorder, physical activity):- idleness, boredom, nervousness, and other problems can lead to excessive food consumption.

  27. Owner factor (Overfeeding):- many owners tend to give their pets the same food they eat, in addition to their own.

  28. Diet:- unbalanced diets can affect the energy balance and, consequently, overweight.

  29. Sterilization:- desexed (neutered) animals spend less energy.

  30. Hormonal disorders:- hyperinsulinemia (excessive insulin in the blood), hypothyroidism, and hyperadrenocorticism or Cushing's syndrome.

  31. Owner's lifestyle and obesity:- research shows that owner body mass index is positively correlated with dog body condition score in the dog population

  32. Medication e.g. corticosteroids and phenobarbital increase appetite.

  33. Concurrent diseases e.g. osteoarthritis, pancreatitis, diabetes mellitus, heart disease, cruciate ligament rupture, intervertebral disk prolapse and insulin resistance lead to decreased activity encouraging weight gain.

Obesity and your pet's health - what is the relationship?


In humans, obesity and its relationship to certain diseases are well-known. Similar relationships exist in the companion animal population, and there are relative risks associated with it because fat tissue is biologically active, secreting inflammatory hormones and stress the body’s tissues, contributing to many diseases. Therefore, obesity is a chronic, low-level inflammatory condition that impacts a dog’s health and longevity.

Obese cats and dogs, therefore, develop an increased risk for:

  1. Many types of cancer

  2. Diabetes mellitus,

  3. Heart disease and Hypertension

  4. Osteoarthritis and faster degeneration of affected joints

  5. Urinary bladder stones

  6. Anaesthetic complications as they are less heat tolerant

Obesity may also be an indicator of diseases, such as hypothyroidism (an underactive thyroid gland) or Cushing’s disease (overactive adrenal glands).

How is Obesity Diagnosed?