For cat owners, seeing their feline friend suddenly drop weight can be a little worrying. While you may briefly be impressed with your cat’s new, slinky figure, there could be a number of explanations for weight loss in cats. Some of them can lead to serious consequences.
As a general rule, there are four broad reasons why a cat may lose weight. They are: psychological reasons, disease or pain, problems processing food or losing nutrients, or using too many nutrients. Let’s look at each explanation in more detail.
1. Psychological reasons
If your cat is eating less than normal, the first question that’s asked is why? Cats as a species have a reputation for being picky. Maybe you’ve changed the brand of food you buy for them, and they hate it. They just won’t eat it. You can’t reason with a cat, so changing back to their favourite brand may be the answer here.
2. Pain and disease
If your cat has dental problems, losing weight may be your only indication something is wrong. If they do have dental problems, those may result in a painful mouth. No-one likes to eat when it hurts—they can’t physically eat or swallow properly. That can be very subtle and hard for the owners to pick up.
They could also feel sick or nauseous from a different disease altogether. That could mean that they are choosing not to eat because they feel sick all the time.
3. Problems processing food or losing nutrients
Another possible reason for weight loss in cats is that they’re not processing their food properly. Possible causes of that could be having diabetes, or irritable bowel syndrome, or even a tumour in their intestines. It could be their pancreas isn’t working properly. We would also want to check to see if there are signs of heart disease, which can sometimes cause problems in other organs like the liver.
Diseases can also cause cats to lose nutrients. That can be a result of having tumours in your body that are causing protein or nutrient loss. Kidney disease will cause weight loss, as well as a myriad of other problems.
4. Problems with increased use of nutrients
Sometimes the cat will be eating huge amounts but still losing weight. Depending on the age of the cat, the root cause of that problem may be a high burden of gut parasites of various different sorts (which is common in young cats).
It can also be a relatively common condition called hyperthyroidism. Hyperthyroidism is a metabolic disease. Although you’ll obviously need a vet to diagnose it, some of the indicators of hyperthyroidism are behavioural.
One thing you may notice (other than the weight loss) is the cat gets very restless. A symptom of the condition is having a racing heart beat—the cat equivalent of constant anxiety. They’re very reactive to other cats, and to you doing things. They don’t seem to want to settle.
With this condition, they frequently get high blood pressure. When you try and lift their head up, they get really angry. And the theory is—and I stress, it’s a theory, no-one’s proved it—that the cat has a constant tension headache from having that high blood pressure.
One of the other symptoms is they often have a poor hair coat, which is because they’re not grooming. Normally grooming is something they do that’s pleasurable and nice, and they do it when they’re feeling relaxed and happy. But they stop doing it when they have hyperthyroidism.
Why it’s important to investigate weight loss in cats
Any of those conditions I’ve described above are going to be unpleasant for your cat. But it’s particularly important to rule out the last one, hyperthyroidism. It’s important because it has very unpleasant long-term consequences.
If you have high thyroid hormones in your system, it causes heart damage. It directly damages the heart muscle, as well as making the heart race. I don’t have to spell out the serious consequences of having heart disease.
It can also result in a horrible painful disease called thromboembolism, where a blood clot forms and then detaches and lodges in a blood vessel. It cuts off all the blood to that limb, and it’s excruciatingly painful for them. And it can be irreversible. We end up having to put the cat down because they can’t walk.
It also causes kidney damage, and you need your kidneys to survive. And it can cause high blood pressure. That leads to more heart damage, more kidney damage, but also it can cause brain damage, and they can suddenly go blind. So you don’t really know anything’s wrong, and then suddenly your cat cannot see at all.
In conclusion, don’t ignore weight loss
So while you may be impressed with your cat’s new, svelte figure, don’t assume that sudden weight loss is a good thing. There may well be a price to pay later on down the track. You want the cat in your life to remain happy, healthy and loving—and being the cat equivalent of “the biggest loser” will not lead to that.