Why is my older cat losing weight?

by | Oct 11 2021

As pet parents, we are no strangers to closely monitoring meals and snacks in a bid to fend off obesity in our cats and dogs. So focused are we on this issue, that we are often taken by surprise when the opposite problem occurs, and our pets begin to lose weight with no apparent explanation.

When it comes to our feline friends – particularly those in their senior years – there can be a number of causes that contribute to sudden or gradual, steady weight loss. Here is the lowdown on why your older cat might be losing weight – and what to do about it.


How much weight loss is too much?

There are a number of red flags to look out for if you feel your cat is losing a dangerous amount of weight.

Examining your cat from above, look out for the following signs:

  • Are their ribs and the bones along their back more visible than before?
  • Do their bones feel very prominent?
  • Is their waistline more pronounced than it used to be?

If your cat meets the above criteria, it’s time to consult your vet for advice – particularly if these physical signs are paired with a change in appetite, such as eating too little or eating a lot.


What are the causes of cat weight loss?

You’ve identified that there’s an issue, but what could be the cause?

There are a number of underlying medical complaints that could lead to a cat experiencing weight loss, along with appetite irregularities. If your pet is refusing to eat, or perhaps consuming very little quantities in comparison to their usual portions, it could be a sign of anorexia. This may lead to a condition commonly referred to as fatty liver syndrome – or hepatic lipidosis; a life-threatening issue that requires urgent medical attention.

On the flip side, if your cat is eating as normal – or more than they usually would – and is still losing weight, this is also cause for alarm. It could spell bad news in the form of intestinal parasites or hyperthyroidism – a condition very common in older cats.



While hyperthyroidism can be diagnosed in cats as young as six, it is more commonly associated with our senior feline friends. Signs of this disease include overeating paired with weight loss, drinking and urinating excessively, diarrhoea and vomiting. Because of an overactive thyroid, or potentially a tumour on the thyroid gland, calories from food are quickly depleted as a result of increased metabolism. If you suspect that your cat may be suffering from hyperthyroidism, contact your vet immediately to avoid any further medical complications.

Gastrointestinal disease, including intestinal parasites:

Inflammation of the digestive tract can cause a host of problems for your pet, as can the presence of parasites in the intestine, which may take the form of worms. Both issues prohibit the absorption of essential nutrients from the food they eat. This naturally leads to weight loss, and can also cause symptoms such as nausea, vomiting and diarrhoea.

Kidney disease:

While increased drinking and urination is a sign of hyperthyroidism in your cat, it can also point to kidney disease. This particular medical issue can also interfere with appetite, making weight loss a sign to watch out for.

Diabetes Mellitus:

Sharing many of the same symptoms, diabetes can also cause weight loss among cats, along with excessive drinking, urination, sluggishness and possibly even urinary tract infections.


Why is my older cat losing weight 3 - Mark + Chappell

How to treat weight loss in older cats

While all of the above causes of weight loss can affect cats of any age, they are familiar conditions found among the more senior members of the feline population. So, how can you help your cat to gain weight and get to the bottom of the medical issues they’re experiencing?

First things first – a trip to the vet is the most urgent course of action to ensure that your beloved pet is diagnosed and treated accordingly. Depending on the seriousness of their condition, treatment may come in the form of medication, surgery, or you may simply be advised on how to implement necessary dietary changes.

If you want to take preventative steps to ensure your older cat’s nutritional needs are supported, a supplement that supports the specific needs of senior pets can boost immune and brain health, while also increasing energy and protecting ageing joints.

Another way to prevent specific medical issues, such as parasites, is to ensure you adopt safety measures with the food you give your cat (no raw meat, please!) and to keep their play, rest and litter areas properly sanitised.


Taking care of your older cat

The general consensus is that cats reach middle age at around seven years old. From this point on, it is important to take note of any significant physical, behavioural or dietary changes they may be displaying, which could require a visit to your vet for further investigation.
Oftentimes, weight loss is simply a natural part of ageing for many cats, but an expert opinion will give you peace of mind when it comes to your prized pet.


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