Obesity in pets is becoming a serious problem. No matter how cute they look and how much we love those ‘chunky’ dogs and cats too, obesity should not be trivialised. Obesity carries a huge range of health conditions and generally results in a poorer wellbeing for our pets. Knowing whether a pet is obese can be difficult for us as vets and owners too. Weight management itself is a vast and complex topic. Today we will be discussing how best to recognise obesity in pets (with a focus on dogs and cats).
The Ins and Outs of Obesity
We should probably start with the obvious questions: what is obesity and when is a pet considered obese?
What is obesity and what does it do?
Obesity is simply defined as having excess body fat. However, this does not put emphasis on the complex biochemical and physiological changes excess body fat brings to the body. In brief, excess fat (or adipose tissue) releases too many chemicals, called adipokines. Adipokines cause chronic low grade inflammation (similar to having a long-term disease), which damages cells, tissue and organs. Many of these changes are irreversible. One big consequence is that the pathway responsible for metabolising fat is altered. This makes it easier for obese fats to take in fat and reduces their fat breakdown. In other words, fat pets are more likely to get even fatter! A number of diseases are linked to obesity, including diabetes, arthritis and degenerative joint disease, liver disease, Cushing’s disease, pancreatitis, some cancers, cardiovascular problems and many more. Obese pets will usually have shorter lives and often die due to complications with obesity.
The chronic changes linked to obesity are why we now like to refer to the condition as a chronic inflammatory disease. There is some evidence that certain breeds are predisposed to obesity. Certain diseases cause obesity but the number one cause of obesity in pets is excess calories (either too much food, or the wrong type of food) combined with not enough exercise.
Identifying obese pets
Identifying obesity in pets can be tricky, especially in the early stages where it may not be physically obvious. The effects of obesity get worse the more obese an animal is. Therefore identifying it early when changes can be made is crucial. An important thing to remember is that 50% of excess fat is stored internally, surrounding organs. So however obese your pet looks from the outside, add half again to include internal fat, all of which is producing adipokines and damaging organs.
The simplest method to judge if a pet is overweight is to look at their silhouette, from the side and from above. There are plenty of charts online that show the ideal body shape for dogs and cats which can be compared to your pet. Larger pets are generally rounder, bones like the ribs are less defined, and they have bulging hips.
A better method is to regularly weigh a pet. This can be done at home, so it is great for owners to do this regularly too. Little changes in weight may be incidental, but keeping records that show a gradual upward trend can be a good early warning.
Finally, probably the best method of identifying obese pets is using body condition score (BSC). BSC is where you feel certain areas of a pet’s body (ribs, hips, abdomen, spine and neck are all common areas) to feel for fat coverage. Fatter pets will feel softer and the underlying bones will be hard to feel. A score can then be given, on a 1-5 or 1-9 scale, with higher numbers indicating excess fat, thus obesity. Vets can easily teach you, so it can be performed at home.
Sadly, there is no one perfect method of identifying obesity in pets. Often chronic damage has already been done before obesity is noticed. This is why preventing obesity is so important. However, as many pets are already obese, the next article will focus on how these chunky cats and dogs can be slimmed down.