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.
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:-
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).
Gender: Neutered dogs have the highest prevalence with the lowest prevalence in intact males.
Breed (Genetics): Certain breeds are more prone to overweight and obesity than others.
Dog breeds that are predisposed to weight gaining:-
Cavalier King Charles Spaniel
English Cocker Spaniel.
Labrador Retriever
Dalmatian
Dachshund
Rottweiler
Golden Retriever
Shetland Sheepdog
Mixed-breeds.
Cat breeds predisposed to weight gaining:-
Maine Coon,
Norwegian Forest Cat
Himalayan
Neva Masquerade,
Cornish Rex
British Shorthair
Ragamuffin
Chausie
Siberian
Savannah
Domestic Shorthair
Lifestyle (Behavioural disorder, physical activity):- idleness, boredom, nervousness, and other problems can lead to excessive food consumption.
Owner factor (Overfeeding):- many owners tend to give their pets the same food they eat, in addition to their own.
Diet:- unbalanced diets can affect the energy balance and, consequently, overweight.
Sterilization:- desexed (neutered) animals spend less energy.
Hormonal disorders:- hyperinsulinemia (excessive insulin in the blood), hypothyroidism, and hyperadrenocorticism or Cushing's syndrome.
Owner's lifestyle and obesity:- research shows that owner body mass index is positively correlated with dog body condition score in the dog population
Medication e.g. corticosteroids and phenobarbital increase appetite.
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:
Many types of cancer
Heart disease and Hypertension
Osteoarthritis and faster degeneration of affected joints
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?
Overweight or obese animals usual present with the following Clinical signs
Bodyweight about 15% above maximum weight for the breed, age, sex
Loss of visible waist (unable to feel the ribs).
Pendulous abdomen
Fat accumulation on either side of tail-head and over hips
Abnormal 'waddling' gait
Decreased exercise tolerance.
Poor coat and skin condition.
The diagnostic investigation is done by carrying the below procedures:-
Body condition score (BCS) using a recognized scheme, e.g., the 9-integer scale system.
Weight with accurate and precise electronic scales.
Routine clinicopathological investigations, if warranted.
Consider measuring thyroid function Thyroxine assay (free)
How is Obesity Treated?
There are only two ways to lose weight:
Increasing the amount of energy used, ie taking more exercise.
Reducing the number of calories taken, ie eating less food.
Owner Education:-
To accept the problem.
To alter behaviour in terms of feeding and exercise.
Assess initial status
Animals are weighed by using the same set of scales each time.
A bodyweight target is set on the body condition score chart (1 unit between 5 and 9, on a 9-point body condition score, represents 10-15% excess weight Body condition scores ).
A time to reach the target body weight is set.
Dietary management
A reduced-calorie diet designed for weight loss should always be used. Diets with high protein and high fibre work best for excessive body weight.
The diet is started by providing 50-60% of maintenance energy requirements AT TARGET BODY WEIGHT and the level of intake monitored regularly and adjusted if required.
The diet is fed at least twice daily.
Electronic weighing scales should always be used to measure out food - NEVER use a measuring cup.
The dog should be kept out of the room when food is prepared or eaten.
Feeding extras should be avoided; if it is a must to give treats, a portion of the daily food ration should be used.
Drug therapy
Mitratapide and Dirlotapide are microsomal membrane transfer protein inhibitors that are now licensed for use in dogs but NOT for cats or humans! Mitratapide is designed to be used in conjunction with dietary management during the first 2 months of a weight management protocol.
Dirlotapide can be used for up to a year and the diet need not be changed initially (provided it is properly balanced). However, diet management MUST be employed during the maintenance phase.
Other
Where possible, exercise should be increased taking into account the dog's capabilities (lead exercise, swimming, etc). The minimum exercises should be started if there is gross obesity because of the risk of cardiac or respiratory insufficiency.
Decreased quantities of normal diet should be fed and the owner should not give in to the animals begging. High fibre diets help to reduce this problem. Drug therapy can also be of benefit since most of its effect is through decreasing appetite.
Until target weight reached
Progressively increase exercise to optimize weight reduction.
Maintain a diary, which details the amount fed and eaten, exercise and if any additional food has been fed.
If no significant weight between weight checks, check the diary for possible reasons (eg lack of exercise, additional food given). If there is no obvious reason for the lack of weight loss, decrease calorie intake by 5-10%.
If weight loss is very slow, consider checking for Hypothyroidism if this has not been done before.
Continue weighing every 2-4 weeks. Once the target weight is reached, increase food intake gradually (eg 5-10% a time) continue to check weight. Once the weight is stable continue with regular weight checks (every 3-6 months) to ensure that weight remains stable.
Consider maintaining a moderately calorie-restricted diet for excessive body weight.
How does one prevent obesity in cats and dogs?
Juvenile (Puppies)
The puppy growth curve should be plotted for 18 - 24 months.
Preventing obesity at this life stage prevents obesity in adulthood.
The risks of weight gain after neutering should be realized and food intake adjusted accordingly.
Regular weight checks should be organised to monitor weight gain at this time, e.g., 2 weeks, 4 weeks, 3 months and 6 months after neutering.
Adult
Regular exercise should be encouraged.
A balanced diet to maintain optimum weight should be fed.
Ad-libitum feeding should be avoided.
Frequent changes in diet flavour should be avoided.
Highly palatable table-scraps and titbits should be avoided.
Encourage regular (3-monthly) weight checks.
Discuss weight control after neutering.
Both the body weight and the body condition score should be measured and recorded at EVERY visit in EVERY dog and cat.
References
German, A. J., Holden, S. L., Bissot, T., Hackett, R. M., & Biourge, V. (2007). Dietary energy restriction and successful weight loss in obese client‐owned dogs. Journal of Veterinary Internal Medicine, 21(6), 1174-1180.
Weber, M., Bissot, T., Servet, E., Sergheraert, R., Biourge, V., & German, A. J. (2007). A high‐protein, high-fibre diet designed for weight loss improves satiety in dogs. Journal of veterinary internal medicine, 21(6), 1203-1208.
German, A. J. (2006). The growing problem of obesity in dogs and cats. The Journal of nutrition, 136(7), 1940S-1946S.
McGreevy, P. D., Thomson, P. C., Pride, C., Fawcett, A., Grassi, T., & Jones, B. (2005). Prevalence of obesity in dogs examined by Australian veterinary practices and the risk factors involved. Veterinary Record, 156(22), 695-702.
Lund, E. M., Armstrong, P. J., Kirk, C. A., & Klausner, J. S. (2006). Prevalence and risk factors for obesity in adult dogs from private US veterinary practices. International Journal of Applied Research in Veterinary Medicine, 4(2), 177.
Anderson G L & Lewis L D (1980)Obesity. In: Current Veterinary Therapy VII. R W Kirk (ed). Philadelphia: WBSaunders. pp 1034-1039.
Linder, D. E., Santiago, S., & Halbreich, E. D. (2021). Is There a Correlation Between Dog Obesity and Human Obesity? Preliminary Findings of Overweight Status Among Dog Owners and Their Dogs. Frontiers in Veterinary Science, 736.