Top 10 Cat Diseases Caused By Obesity

Recently Nationwide, the largest provider of pet insurance in the US reported an increase in obesity-related claims for the sixth year in a row. Data from 2015 shows that 1.3 million claims amounting to $60 million US were filed for obesity-related health conditions in cats and dogs, which is up from $54 million US in 2014.

Many pet owners still think obesity is a benign condition but it’s not, there are many diseases directly caused by obesity. I don’t think any pet owner wants to intentionally cause disease in their pets, but that is what is happening when we allow them to become overweight. Not only does it make our cats sick, but shortens their lives. Your cat may look a little tubby on the outside, but on the inside, he is very unhealthy.

Top ten obesity-related diseases

According to Nationwide, these are the top ten obesity-related claims made in 2015.

1. Bladder/urinary tract disease
2. Chronic kidney disease
3. Diabetes
4. Asthma
5. Liver disease
6. Arthritis
7. High blood pressure (hypertension)
8. Congestive heart failure
9. Gall bladder disorder
10. Immobility of spine


Many of the diseases listed above will affect the cat for life. The majority can be managed, and a small number reversed. But obviously, prevention is better than cure or management. Even if your cat does develop an obesity-related disease that can not be cured, losing weight will improve his quality of life and help manage the disease.

Why are pets getting fatter?

Up to 58% of cats in the US are now obese. That’s right; nearly 6 out of 10 cats are obese. The definition of obesity is over 30% over the ideal body weight.

First and foremost, many pet owners don’t realise their pet is overweight, if they don’t recognise there is a problem, they can’t fix it which is why it is so important to take your cat to a veterinarian regularly to have his health and weight monitored.

Many pet owners are choosing to keep their cats exclusively indoors, which is fantastic. The dangers to cats who are allowed to free roam have been repeated over and over again. Cars, people, dogs, diseases all pose a threat to outdoor cats. So we certainly don’t want to discourage cat owners from keeping their cats safe indoors. However, the downside of this is that cats are becoming more sedentary and this is reflected in the growing number on the scales. There are several solutions to this.


Get kitty moving. Cat enclosures are an excellent compromise for cats, they enable your cat to enjoy the benefits of the great outdoors (sun, smells, watching the world go by), but they are safe.

Enclosures can range from a small deck or balcony to positively palatial. If space permits, provide your cat with multiple ledges to climb.

If you don’t have the space for an enclosure, your cat can still get his daily activity outdoors on a harness. Not all cats will respond to a harness, but many do — particularly those who have been introduced to one early on.

Designate 10 – 15 minutes twice a day to play with your cat. There are several different types of cat toys on the market. Wand toys and lasers (be careful not to point them in your cat’s eyes) are particularly good to get your cat exercising. It’s a great way to increase your cat’s activity level and spend time bonding.


We need to tailor the amount of food our cats eat to their age and lifestyle. A sedentary cat is not going to need to eat as much as a cat who is roaming outside, just as an athlete needs to consume more calories than a couch potato.

For the past 20 years or so, we have been encouraged to feed our cats dry food. Dry food is convenient to feed, and most of us are very busy people. It allows us to fill up their bowl with far more food than they need and let our cats eat when they are hungry. This can work for some cats, but others will overeat if they are given a chance.

Many people equate food with love and can quite literally love their cat to death. They are feeding excessively large meals, allowing cats to free-feed (if they are prone to obesity or over-eating), sharing human food and giving treats.

What not to do

  • Don’t give your cat treats, table scraps or free-feed if the cat is prone to obesity.
  • Don’t feel sorry for your cat as he begs for more food. Think about the bigger picture, his future health.
  • Only provide water to drink which has zero calories.


  • One person should be in charge of feeding; that way the cat won’t inadvertently be fed twice.
  • If he does beg you for more food, try distracting him with play, or groom him or even some clean and fresh water.
  • Leave food down for 20 minutes and remove any uneaten food.

How do I know if my cat is overweight?

It is easy to determine if your cat is overweight or underweight by feeling the body.

  • The underweight cat will have easily palpable ribs, spine, and hips. There will be an apparent abdominal tuck.
  • The cat within the healthy weight range will have ribs that can be felt, but with a slight fat covering. As you stand above your cat, he should go in just behind the shoulders and again, just in front of the hind legs.
  • The overweight cat will have ribs that are not palpable, large stores of subcutaneous fat and no waist.

How much should a cat eat?

According to DVM, the best way to calculate your cat’s daily requirements is to use this simple formula. This calculates your cat’s RER (resting energy requirements) which is the amount of energy (in calories) expended in a day without any activity; it is similar to basal metabolic requirements.

Once you have calculated your cat’s RER, the formula then shows how to calculate your cat’s DER (daily energy requirements) which is several calories your cat should eat.

How to calculate a cat’s daily energy requirements

Calculate your cat’s resting energy requirements: 30 x your cat’s body weight in kilos (1 kg = 2.2 lbs) + 70. So, let’s look at some examples below.

  • Average cat who weighs 5 kg: 30 x 5 kg + 70 = 220 is your cat’s RER
  • Kitten who weighs 1 kg: 30 x 1 kg + 70 = 100 is your cat’s RER
  • Obese cat who weighs 6.5 kg: 30 x 6.5 kg + 70 = 265 is your cat’s RER

Now you have your RER (resting energy requirements), you need to calculate your cat’s DER (daily energy requirements). To do this, you take your cat’s resting energy requirements and then apply the following formula.

Calculate your cat’s daily energy requirements:

  • Growing kittens RER x 2.5
  • Normal desexed adult (maintenance) RER x 1.2
  • Intact adult RER x 1.4
  • Obese prone RER x 1
  • Weight loss RER x 0.8

Now to calculate the DER (daily energy requirements):

  • A 5 kg cat who is on a maintenance diet and doesn’t need to gain or lose weight. 220 RER x 1.2 = 264 calories per day.
  • A 1 kg kitten who is growing. 100 RER x 2.5 = 250 calories per day.
  • A 6.5 kg obese cat who needs to lose weight. 265 RER x .8 = 251 calories per day. As your cat loses weight, his RER will drop, and you should adjust this formula. The same goes for kittens, a kitten’s weight will gradually increase, and therefore you will need to recalculate his daily energy requirements weekly.

Allow a pregnant and lactating female to eat as much food as she wants. Pregnancy and lactation use a considerable amount of the female’s resources, and she should be fed to accommodate these extra needs.

A word of caution

Weight loss in cats can be dangerous if it is too rapid. Cats can develop a condition known as hepatic lipidosis which develops when a cat becomes anorexic (stops eating) or reduces the amount of food he consumes. The body begins to use fat as fuel, which is sent to the liver to be processed into lipoproteins. However the cat’s liver is not very good at processing fat, and it begins to accumulate in the liver cells (hepatocytes), overwhelming it and interfering with its ability to function.

All weight loss should be carefully monitored by a veterinarian to make sure it is done safely and slowly. See your veterinarian if your cat displays any of the following symptoms.

  • Loss of appetite
  • Drooling (due to nausea)
  • Vomiting
  • Yellow mucus membranes
  • Lethargy
  • Depression
  • Dehydration

It may take several months for your cat to lose weight (depending on how much he needs to lose). Be patient and remember you are doing this for your cat. Both your cat and your wallet will thank you.


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

    View all posts