What does obese actually mean?
Obesity is defined as a cat who is 20% (or more) heavier than their ideal lean weight due to excessive fat. An overweight cat is defined as being between 1% and 19% over their ideal weight.
However, this is a scientific description that, although very useful for research, is less helpful in the real world – because it’s very hard to determine what a cat’s lean weight is without a CT or MRI scan! As a result, we tend to use the Body Condition Score (BCS) of a cat to estimate whether they are obese, overweight, underweight, emaciated or just right. Our vets and nurses are trained to use a scale of 1-5, where 2 or 3 is ideal.
These work out as:
- BCS 1/5:The cat is emaciated.
- They have no significant fat cover and the ribs, spine and pelvis are easily visible even if the hair is dry on short haired breeds.
- Their bones feel sharp under their skin.
- They have a severe abdominal tuck, where the belly disappears into the pelvis.
- They may have severe muscle wasting as their body breaks down muscle to try and stay alive.
- BCS 2/5: The cat is underweight.
- The ribs are visible on shorthaired cats, especially if the coat is wet, but the pelvis is not clearly seen.
- There is an obvious waist and the belly is tucked up.
- BCS 3/5: The cat is just right, and is at about their ideal weight.
- Their ribs cannot be seen, but can easily be felt.
- They have an obvious waist.
- There is a little bit of abdominal fat covering but it doesn’t ooze or hang down.
- BCS 4/5: The cat is overweight to obese.
- The ribs are difficult to feel under the fat.
- The waist is barely visible.
- The belly is rounded with a small skirt of fat.
- BCS 5/5: The cat is morbidly obese.
- The ribs cannot be felt even with pressure.
- There is no waist.
- The abdomen is swollen and distended with fat.
- There are fat deposits under the skin.
Each step in the score over 5 represents about 10% excess fat.
Why do cats get obese?
There are a number of factors, but the most important is that people feed them too much! With high calorie food easily available, the majority of cats will eat and eat until they are overweight or obese. As owners, it is our job to prevent that from happening.
A more insidious factor is that most cat owners do not know what a healthy animal should look like – if asked to score their own cats, most people rate them as lower than they actually are. In fact, most people think a BCS 7/9 cat is ideal not overweight; and many believe that a 5/9 cat (who is ideal) is malnourished and needs more food. It’s really important that you learn what your cat is supposed to look like!
But is obesity actually harmful?
Yes. There’s no question about that any more – obesity in cats significantly increases the risk of a number of unpleasant diseases.
For the following diseases and conditions, obesity is well recognised to be a risk factor:
- Lower Urinary Tract disorders such as cystitis and FLUTD.
- Skin disease (not allergies, but other problems such as pyoderma).
- Fatty Liver Disease (hepatic lipidosis).
- Decreased ability to exercise.
There is also evidence, although it is not yet conclusive, that obesity in cats contributes to:
- Increased risk under a general anaesthetic.
- Decreased immunity.
- Difficulty giving birth (dystocia).
- Heart disease.
- Increased risk of tumours or cancer.
- Shorter lifespan.
So what should I do about it?
The bottom line is that an obese cat should be fed fewer calories! This may be a matter of reducing how much you put in their feed bowl at each meal – but unfortunately, if they think they’re being starved, some cats will respond quite badly!
A better solution is to use a properly formulated weight control or weight reduction diet, that encourages a sense of fullness while providing fewer calories. But don’t feed extra!
Also, remember – treats and snacks form part of the daily diet, so take them into consideration!
A crash diet is the worst thing you can do – in obese and overweight cats, it can trigger liver failure. It’s much more important to lose the weight gradually over weeks and months – roughly 1% body weight per week is usually optimum.
The best thing you can do if you are concerned about your cat’s weight is to bring them in for a weight appointment with one of our nurses, who will be able to advise you and help formulate a diet plan.