Fat black and white cat

Overweight cats may suffer from various health conditions.

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What should I do if my cat is obese?

By Dr. Pete Wedderburn, BVM&S CertVR MRCVS Veterinarian

Updated on the

Through too much food and not enough exercise, cats can soon become overweight, but the right regime can soon get them back on track.

Excessive body weight is a common problem in cats, with studies showing that between 40 and 60% of cats are overweight or obese. Cats often gain weight without their owners noticing or realising. This article aims to explain the problem in detail, along with suggestions on how to ensure that your cat is a healthy weight to ensure optimal pet health.

What’s the difference between an overweight and an obese cat?

Cats are ‘overweight’ when they are 10% to 20% per cent heavier than their optimal weight, and “obese” when they are over 20% heavier than ideal. Both conditions are caused by consuming too many calories by eating too much, and not burning up enough calories through activity.

What is an obese weight for a cat?

It is impossible to say precisely what a cat should weigh, because as with humans, the underlying body frame of a cat varies significantly in size. Some petite female cats may be overweight at 4kg, while a large, muscular male cat could be a healthy weight at 7kg. That’s why other methods are needed to determine whether a cat is at a healthy weight.

How can you tell if a cat is obese?

Instead of the cat’s weight, the best method is to use the cat’s Body Condition Score. Typically, this classifies cats into five categories as follows:

Score 1. Thin. Underweight, with bones of legs, spine and ribs easily visible.

Score 2. Lean. The skeleton is visible, but bones are not obviously protruding. The cat has a markedly tucked-up abdomen and a very obvious waist.

Score 3. Ideal weight. The underlying skeleton can be felt when the cat is petted, but the bones are not visible. The cat has a tucked-up abdomen and a waist that is narrower than the chest area.

Score 4. Overweight. The bones of the skeleton (especially the ribs) cannot be felt easily when the cat is petted. The cat’s abdomen is drooping down and the waist area is the side width, or wider, than the chest area.

Score 5. Obese. The bones of the skeleton (including the spine and ribs) cannot be felt at all under the layer of body fat. The abdomen is swollen and wider than the chest area. The cat suffers from physical difficulties caused by excessive weight, limiting activities like moving around, running, jumping, etc.

Is 17 pounds too heavy for a cat?

Yes. It is possible that a large muscular cat of certain breeds (e.g. Maine Coon) could normally be this heavy, but for most cats this would indicate obesity.

Is 15 pounds heavy for a cat?

This probably indicates obesity, but certain breeds of cat could be at a healthy weight of 15 pounds. Assessment of Body Condition Score is important.

Is 13 lbs overweight for a cat?

Some large cats are at a healthy weight at 13lbs, but for most cats, this would suggest obesity. A proper Body Condition Score assessment should be carried out.

Why does my cat have a big belly?

Excess weight is the most common cause of a big belly in a cat, so you should carry out a Body Condition Score assessment to determine whether or not your cat is overweight or obese. Some older cats with a healthy body weight do have a droopy abdomen, just like some middle-aged and elderly people have larger abdomens without necessarily being overweight, which is why it’s important to assess the other aspects included in the Body Condition Score.

Do worms make cats fat?

Worms could never make cats obese, but a heavy worm infestation could cause a distended abdomen (“pot belly”). In such cases, the other aspects of the Body Condition Score will prove that the cat is lean, but with a swollen abdomen. For example, you will be able to feel the bones of the spine and the ribs. In such cases, you should give your cat a worm dose, or have them checked by the vet for other causes of a distended abdomen.

Why is my cat obese?

Cats become overweight or obese if they eat too much food and don’t take enough exercise, just as with humans. High-quality, tasty food is often offered too readily to cats, and they just eat too much. Also, neutered/spayed cats and older cats have a lower calorie requirement than most people realise, and so the owners accidentally feed their pets too much.

How do you treat an obese cat?

The answer is simple in theory: feed your cat fewer calories and encourage more activity. In practice, just as with humans, it’s more complicated. Obese cats often love their food so much that they don’t like it to be restricted, and they have developed a lazy habit of just lying around, so they don’t like being active. The best answer is to engage with the local vet clinic to get assistance from professionals (often veterinary nurses). Weight loss has to be managed properly: if a cat loses too much weight, too quickly, they can develop a dangerous disease condition known as hepatic lipidosis. This is why professional help is so important.

There are three key aspects to weight loss in cats:

First, weigh your cat regularly e.g. every two weeks. It’s best to do this on accurate, electronic scales at a vet clinic and then the weight can be recorded on the cat’s records, allowing a graph to be drawn up showing progress.

Second, feed your cat a measured amount of a cat food designed to help cats lose weight. There are different versions of this: high-fibre foods and high-protein/low-carbohydrate foods. Both these food types make cats feel more full with fewer calories.

Third, get your cat to do more activity. You can do this by playing with them more, by hiding their food in toys so that they need to do physical work to find it, and by designing their home environment to encourage them to move around more (for example, using a cat tree to get them to climb into their bed).

How do I get my indoor cat to lose weight?

Indoor cats are a particular challenge as they tend to move around less than cats going outside. You need to make more effort to play with them, to use their environment to encourage them to be climb (e.g. a cat tree) and to use food-releasing toys that encourage them to be active. The best approach is to engage with a weight-management programme at the local vet clinic.

How long can an obese cat live?

The average lifespan of a cat is from 12 to 18 years, but fat cats are prone to a number of health problems, which are likely to significantly shorten their lives. This includes diabetes, heart disease, liver disease, arthritis, urinary tract disease and skin disease.

Can a cat die from being overweight?

Obesity is unlikely to kill a cat in itself, but overweight cats are more likely to suffer from a number of different conditions leading to their premature death.

How can I stop my cat from becoming obese again after reaching their ideal weight?

When a cat is at a healthy weight, you then need to feed a daily measured amount of food on a long-term basis, as well as continuing to encourage an active lifestyle

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