How to tell if your cat is underweight

Just as our cats can gain weight, they can also lose it too. Take a look at our free guide to find out how to tell, and what to do, if your cat is underweight.

Is my cat too skinny?

As owners we all want the best for our cats. When you go to the vet for check-ups or vaccination boosters they will likely weigh your cat then and let you know if you should be worried.

Weighing your cat at home isn’t always the best way to tell if they’re underweight. Cats come in all shapes and sizes. If you’re worried your cat has lost weight or is too thin, we’d recommend taking a look at their body condition to judge whether your cat is the right weight.

Signs that your cat is too thin or underweight

Your cat may be underweight if it’s easy to see and feel their ribs.

Owners hands on the ribs on a cat showing underweight cat

Or if their belly is noticeably tucked behind their ribs.

Illustration of an underweight cat, with an arrow pointing to their belly

Their hip and lower back bones will be clearly visible.

Illustration of an underweight cat, with an arrow pointing to their hips/lower back

And their spine can be easily felt and seen.

Owners hands on the back/spine on a cat showing underweight cat

Healthy cats should have a thin layer of fat covering their bones.

Illustration of a hand on a cat’s back whilst they are ideal weight

If your cat is the correct weight, you will:

be able to feel their ribs, but not see them (there should be a little fat on them)
be able to feel their backbone, but again not see it
be able to see their waist tuck in slightly behind their ribs if you are looking down at your cat’s back

What to do if your cat is underweight

If you think your cat is underweight, make an appointment with your vet as they are best placed to assess your cat’s body condition and can rule out any underlying medical problems that might be causing weight loss. You should also look out for a loss in appetite as this can show something is wrong.

Your vet will be able to give you the best advice for your cat moving forward, which may include a special diet or medication to manage any conditions they might have. They can also help you to find the cause of your cat’s weight loss if there are no obvious medical reasons.

What causes cats to lose weight

Cats can lose weight for a number of reasons, including:

their age – older cats are more prone to health conditions that can affect their weight and muscle tone so it’s important to keep an eye on them
medical problems – there are lots of medical conditions that can cause your cat to lose weight, such as dental issues, gut issues, arthritis, hyperthyroidism and kidney disease. It’s important to keep up with regular visits to your vet (cats over eight years of age should see the vet twice a year ideally) as well as preventative healthcare such as flea and worming treatments and vaccinations. Take your cat to the vet sooner if you feel they are losing weight
stress – sometimes a stressed cat may go off their food which can cause them to lose weight. Find out more about stress in cats
being more active – if you have an outdoor cat, you might find that in summer months they go out exploring more. The extra exercise might cause them to lose a bit of weight

How to encourage your cat to eat more

If your cat is underweight your vet may advise you to encourage them to eat a little more. They will also be able to tell you what can and can’t be offered, as some foods may make underlying illnesses worse. Sometimes it can be difficult if your cat doesn’t seem interested in their food, but there are a few things you can do to get them to eat:

make sure their food bowl is kept away from their sleeping and toilet areas and isn’t near a door. Find out more about creating the perfect environment for your cat
make sure you’re offering them the right type of food for their age and according to what they prefer. Some cats may prefer wet food and others dry
offer them food throughout the day if they prefer to graze
try using a feeding toy as this will appeal to their natural hunting instincts
clean their bowl with soapy water every day and rinse well. Cats are very sensitive to smells so if you pile new food on top of old food they’ll be less likely to eat it. You should also try to use an unscented soap
change their food bowl to a different type. Cats tend to prefer wide bowls and some don’t like plastic ones, so try them with a new bowl
try offering them a different type of food if your vet suggests this – they may not like what’s currently on offer. Remember, if you change your cat’s food this should be done slowly and carefully so they don’t get an upset stomach
put a bit of something they do find appetising – such as plain cooked chicken – with their usual food (check with your vet that this won’t cause any problems first)
add a little water from a tin of tuna (not brine) to their food. Again, check with your vet before doing this just to be sure it won’t make any existing issues worse