Cat Weight Issues – Catmart
cat weight issues

Cat Weight Issues

Weight is a problem that’s ever-present, both for people and for pets. More people worry about weight now more than ever. As it turns out, cats should be worrying about their size too.

What cat weight issues can cats get? Diabetes, obesity, underfeeding, hyperthyroidism and IBS can all affect cats. Each condition has different causes which are explored below. The fix is usually diet related. A cat’s average weight is determined by what it eats more than how much it exercises. For more information, consult our diet guides.

Helping your cat get to the right weight is easy. Just adjust their diet—your cat can only eat what it’s given. Don’t expect these problems to fix themselves, or think you can get your cat to lose weight overnight. It doesn’t work like that!

Cat Weight Issues

Cats come in all shapes and sizes. Whilst some breeds such as Bengals will be more slender, others will be more rotund. With some breeds of cats, it’s hard to tell what’s fur and what’s fat. Finding out is important, because just like there’s such a thing as human weight issues, there are also cat weight issues.

Yet, it’s important to ensure that your cat keeps to a healthy BMI weight. Yes, they can look adorable when they pack a few extra pounds, but this will be putting their body under stress. With the right diet and exercise, your cat can live a long, and happy life.

Cat Weight Issues Can Affect All Cats

cat weight issues
“What do you mean I’m looking a bit heavy?” Finding out your cat is overweight can be surprising for both you and your pet! Image from Max Pixel

All cats, regardless of age and breed require a complete and balanced diet. What kind of diet they need will be based on their age, the amount of exercise they get and their breed. It is now easier than ever to pick up competitively priced age-appropriate cat food. This will ensure they are going to get the necessary vitamins to boost the immune system and say healthy. Stay away from the ‘one size fits all’ foods. Your cat will have different energy requirements at different stages of their lifespan. Food intake should also be adjusted regularly, as cats between the ages of seven and twelve are most likely to carry extra weight. Cat weight issues can occur at any stage of a cat’s life, but older cats are more susceptible.

If your cat could benefit from a reduced calorie diet, there are many formulas available online. Always follow the instructions on the packet unless advised otherwise by your vet.

Making sure a cat gets some exercise may seem like an impossible task. Yet there are plenty of ways to encourage exercises with cats. Cats tend to be more active in the morning. Use that window to use toys with your cat. Encourage natural hunting behavior with laser pointers or fishing rod style toys. But remember, cats are solitary hunters. Be sure to give your cat plenty of time and opportunities for independent play. This is easily achieved by scattering toys around your home.

Whilst obesity is the main issue when it comes to your cat’s weight, there are more issues to look out for. We’ve listed the most common problems below.


Whilst diabetes is a long-term condition, it’s also easily managed. However it is vital that you get your cat’s diabetes in check as soon as you spot the symptoms. As with diabetes in people, there are many types of diabetes that your cat could be susceptible to. Yet the most common in cats is Type 1 Diabetes, also known as Diabetes Mellitus (DM).

DM occurs when your cat struggles using sugar as an energy source. DM will change the way their muscles use energy, if left untreated, this could lead to further illness. After eating, your cat should be able to absorb the glucose from their diet. After absorption the glucose is carried around the body before reaching the organs. This includes the heart other muscles. Before your cat can use the glucose as an energy source, it needs insulin; a hormone produced in the pancreas. Yet, with DM your cat’s pancreas is unable to produce enough insulin. Meaning that energy doesn’t get to travel to the limbs or heart, it stays put. In the absence of glucose, your cat’s organs will use fat and protein instead, giving you an overweight cat. This can then lead to the loss of weight and muscle mass.

Signs Of Diabetes In Cats

Older and overweight cats will be more prone to cat weight issues like DM than younger, healthier cats. Here’s how to spot the signs:

  • Increase in appetite/water consumption
  • Increased urination
  • Weight loss
  • Coat deterioration

Diabetes is easily diagnosed from a simple water sample. If your cat is suffering from DM, there will be a higher sugar content than usual. When high amounts of glucose are present, you may be required to administer insulin at home. This will generally be done alongside a controlled diet. Their progress will need to be monitored at regular intervals until you and your vet have found the perfect balance for your cat.


cat weight issues
Is it fur, or is it extra weight? Pick them up and find out. Image from Flickr

Just as it is unhealthy for humans to be underweight, cats can also suffer the detrimental impacts of obesity.

Obesity is a nutritional disease which is the result of excess body fat. We all like to treat our cats, but over-nourishment can lead to serious life-long problems. Even if your cat is an indoor cat, you still need to give them the ability to exercise. Otherwise they will be at high risk of developing cat weight issues – even if they’re only moderately obese. Their bones, joints, respiratory organs and digestive organs can all feel the impact.

Generally, obesity will impact middle-aged, neutered or indoor cats. It’s fairly easy to notice if your cat is suffering from obesity. Their weight will increase and they will have an unwillingness to exercise. It’s important to get the issue rectified quickly, as obese cats suffer from a reduced life expectancy.

What Causes Obesity In Cats?

Causes of obesity include:

  • Imbalance between energy intake and usage
  • Ageing
  • Hypothyroidism
  • Neutering
  • Unbalanced glucose levels

To diagnose obesity, your vet will assess their condition with a physical examination. This is completed on a nine-point scoring system which will allow you to monitor your cat’s weight. Your vet will then recommend the right diet to follow to get your pet back to a healthy cat weight.


At the other end of the spectrum to obesity, malnutrition is an equally serious cat weight issue.

If your cat is underweight, this can lead to further health issues down the line. There are multiple reasons why your cat may not be able to reach a healthy target weight. Thankfully, it’s easy to spot when your cat is under weight. If you can see a marked indent between their ribs and hips this is a clear sign they have cat weight issues, and are underweight. Your cat may seem lethargic and apathetic to grooming if they are malnourished. Which is why it is important to consult with your vet about your cat’s diet.

If your cat suddenly starts to lose weight, consult a vet immediately.

The possible underlying causes of weight loss include:

Causes of Cats Being Underweight

  • Worms and other intestinal parasites
  • Liver problems
  • Diabetes
  • Cancer
  • Heart Disease
  • Kidney disease

How To Avert Cat Weight Issues In An Underweight Cat

cat weight issues
This tabby is in perfect health, and looking proud of it. Image from Wikimedia

Generally, an adult cat needs between 220 – 335 Calories each day. Whether you chose to feed them wet or dry food, always ensure they are getting the minimum calorific intake. The amount of nutrition your cat needs will depend on their size and age. Make sure to always follow the guidelines on your cats food. However your vet may suggest a high-calorie diet in order to avert possible cat weight issues.

Your cat will need a high protein diet to help them sustain a healthy weight. This can be achieved by feeding your cat 100% meat products. Note that these products are not intended to replace regular feeding. Your cat will still require complete and balanced nourishment.

Always feed your cat in multiple servings a day or try ‘free feeding’ and leave bowls out all day for fussy cats. If your cat is apprehensive to head to the food bowl, try placing their bowls somewhere out of the way.

There are always fun treat options to supplement a diet! Any nutritional treats should only make up 10-15% of your cat’s daily calorific intake.

If you struggle to get your cat’s weight up yourself, your vet may provide vitamin supplements in order to reduce the risk of cat weight issues. We have more detailed advice about underweight cats here.


Hyperthyroidism is a common glandular disorder caused by an excess off thyroxine (T4). T4 effects the bloodstream and organ systems which can mean the condition is easy to spot.

Symptoms of hyperthyroidism include:

  • Weight loss
  • Increased appetite
  • Excessive thirst
  • Hyperactivity
  • Increased urination
  • Scruffy or dull coat
  • Panting
  • Excess shedding
  • Diarrhea (usually affecting 50% of affected cats)

Which Cats Are Affected By Hyperthyroidism?

Hyperthyroidism isn’t breed specific, but almost exclusively affects older cats. Between 12 and 13 years is the average age for onset off the condition. Less than 6% of cases affect cats younger than the age of 10. At the time of writing, hyperthyroidism in felines is considered to be approaching epidemic levels.

Your vet will diagnose the condition using a blood test to test the levels of T4 in the blood.

Treatment options include:

  • Oral antithyroid medication – which can take effect after two weeks of treatment. There may be some side effects to the condition and the treatment will have to be administered
  • Removal of the thyroid of the gland. Whilst invasive surgery is the last option it may be mandatory treatment if the hyperthyroidism was caused by a benign tumor.
  • Radioactive iodine therapy – this is the most effective and safe treatment option. The iodine is administered via an injection and will destroy the hyperfunctioning tissues of the thyroid.

Irritable Bowel Syndrome

cat weight issues
Difficulties at the toilet could indicate that your cat is suffering from IBS. Image from Flickr

There’s no shortage of humans who suffer from irritable bowel syndrome (IBS), and so it should be no surprise that our pets can suffer from it, too. It is, however, harder to spot IBS in cats than it is in humans. The diagnosis is generally confirmed via exclusion. This means that a vet will consider all the other cat weight issues which could lead to your cat being underweight first. Once they’ve been ruled out, IBS will be considered as the probable cause.

How To Tell If Your Cat Is Suffering From IBS

As with all other conditions we’ve discussed so far, diagnosis from a vet is important. You cannot and should not make diagnoses of cat weight issues at home unless you’re a qualified professional. There are some key signs that your cat might be suffering from IBS, though. Here’s what to look out for.

  • Constipation or diarrhea. Extreme changes in your cat’s toilet habits in either directions are a strong indicator that something isn’t right.
  • Abdominal pain. Your cat will meow more than usual if it’s suffering from pain, and may be resistant to being touched. If your cat is exhibiting these symptoms, and there’s no obvious sign of an external injury, abdominal pain may be the culprit.
  • Vomiting. There are many reasons why a cat may vomit, so it’s difficult to assess the probability of IBS on vomit alone. However if your cat is vomiting more than usual and one or more of the above symptoms also apply, it’s time to go to a vet.

How Is IBS Treated In Cats?

That’s down to your individual cat, and the individual approach of your vet. However vets appreciate the potential severity of all cat weight issues, and will have come across similar circumstances before.

The most likely way that IBS will be treated will be a diet and supplementation approach. You can expect to be recommended a balance of fiber and probiotics to alter the way your pet’s body chemistry is working, and make digestion an easier process for them.

Your vet will also consider whether environmental stress is playing a role in your cat’s digestive problems. Cats are creatures of habit. The smallest change – one you haven’t even thought about – may be responsible for your cat’s sudden development of IBS. Consider whether you’ve made any changes to your cat’s routine or environment recently. If so, is it practical to change them back? If it isn’t, consider enriching their environment. Cats can become stressed purely because they’re bored. A new set of cat furniture for their entertainment might be just the thing to get them back on track.

I Have Concerns About Cat Weight Issues – What Should I Do?

While the purpose of this page is to provide information on cat weight issues, we can’t replace the diagnosis of a professional veterinarian. If you’re thinking ‘my cat is overweight’ or ‘my cat is too thin’, best advice is to seek the opinion of a vet and make sure nothing is seriously wrong. Some of the health issues we’ve listed above could have serious consequences if left unchecked, and it’s always better to be safe than sorry.

In most cases, cat weight issues can be resolved with a change of diet or exercise regimen. Therefore if you have an overweight cat or an underweight cat, the advice is the same. Listen to your vet, consider the information we’ve explained above, and before you know it you’ll have a lean mean purring machine once again!

Hi! My name is Jamie Fallon. I run Catmart, an online cat health and cat behavior resource. If I'm not sat in front of my PC—and I usually am—then I'm either spending time with my cats or my other half... Whoever jumps on me or asks me for food first!


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