Obesity in Cats

Obesity in cats is a life-changing and life-shortening illness. 63% of cats in the UK are overweight or obese, with middle-aged, neutered and indoor cats at greatest risk.

Weight gain and obesity develop when your cat takes more energy (food) into their body than they burn up. Obesity in cats is a complex disease and multiple factors may combine to cause it. Unmanaged obesity damages both the quality and length of life of affected cats. But the disease is preventable. And even cats who’ve suffered from obesity for years can regain a healthy weight with the right treatment and ongoing care.



What is obesity in cats?

All kittens start life with the potential to maintain a healthy weight. But, over time, a combination of factors turn the ‘cuddly’ kitten into the ‘chunky’ adult cat. But whatever words we use to describe weight gain, the underlying process and risks are the same.

If your cat consumes more calories than they use up in exercise or body functions, they will gain weight.

  • The excess is stored as a type of fat called ‘white adipose’.
  • Fat cells grow in size and number to store more and more fat.
  • Blood supply to the fat worsens as size increases.
  • Other cells in adipose include defence cells and ‘inflammatory’ cells.
  • As fat increases, the number and activity of inflammatory cells increase.
  • Worsening blood supply ‘activates’ the inflammatory cells.
  • The activated cells release chemical signals which travel throughout the body.
  • The chemical signals trigger inflammation and damage in organs and tissues they enter.
  • New illness may develop or existing illnesses worsen. Including pancreatitis, arthritis, urinary problems and diabetes

Obesity in cats: why does it happen?

Obesity is a complex illness. Lots of things acting together can cause obesity in cats.

Possible factors include:

  • Overfeeding/overeating.
  • An unsuitable or unhealthy diet.
  • Too many treats: especially high fatty, sugary human food.
  • Lack of exercise.
  • Gut dysbiosis: diet in overweight cats causes long-term changes in the bacteria/microorganisms that live in the gut (the gut biome). These changes change the way nutrients in your cat’s food contribute to weight gain.
  • Other illnesses: may affect mobility, appetite and/or metabolism.
  • Boredom: lack of mental stimulation can cause overeating.



Obesity in cats: how can I tell if my cat is affected?

Clues that your cat is suffering from obesity:

  • You may struggle to see or feel your cat’s ribs or backbone
  • Their tummy may be getting rounder
  • Their face and neck appear rounder and collars get tighter
  • Their coat looks matted and poorly-groomed

Your cat may be:

  • Acting more tired and sleepy
  • Becoming less able to reach high surfaces and climb
  • Becoming disinterested in play or going out



The risks of obesity in cats

Factors that increase your cat’s likelihood of obesity include what they eat, their environment and their individual characteristics.

What and how they’re fed:

  • Overfeeding for age, lifestyle and size
  • Feeding an exclusively dry diet
  • Feeding ad-lib or giving small frequent meals
  • Guesstimating amounts of food rather than weighing accurately
  • Feeding treats between meals without reducing main meal portion sizes to compensate
  • Feeding poor-quality food

Environmental factors:

  • Living completely indoors
  • Boredom or lack of stimulation
  • Stress

Cat-related factors:

  • Suffering from other illnesses
  • Being aged 8-12
  • Being neutered
  • Being bored

What are the health complications of obesity in cats?

  • Reduced life expectancy
  • Stiffness, lameness and joint problems
  • Loss of energy, fun and curiosity
  • Increased risk of heart disease, kidney disease, cystitis, a blocked bladder and diabetes,
  • High levels of fat in the blood (hyperlipidaemia) and pancreatitis
  • Certain types of cancer
  • Breathing difficulties
  • Hepatic lipidosis, also called fatty liver syndrome



How can I tell if my cat is obese?

It’s very hard to see gradual weight gain in your cat. Often the first thing any of us realise is when somebody else (often a vet) comments that our cat is overweight or even obese. It’s an unpleasant shock.

Overweight or obese, is there a difference?

  • Cats who are 10% above their healthy weight are classed as overweight
  • Cats who are 20% or more above healthy weight are obese.

There’s not a clear cut-off. Overweight to obese is a continuum. And it’s a path more than half of UK cats will follow.

Body condition score

Vets use body condition score to assess whether your cat is overweight or obese.


Body Condition Score (BCS) is a scale that gives a practical evaluation of the fat coverage of your cat’s body. By checking how easy or not it is to feel certain bony areas of the body, a score is then produced. There are several scales, from 1 to 5 or 1 to 9. The ideal body condition lies in the middle, so either 3/5 or 5/9.

The body areas normally checked for fat coverage are:

1. ribs and spine

2. hips and shoulders

3. waist

Body condition scoring (BCS) in cats

Here are a few tips on how to do it.

With your pet in a standing position:

  • Place your hands on the rib cage and gently feel for each rib, without pressing too hard
  • Feel the waist and look from the top and the side (if you have a very furry breed, it may be harder to assess)
  • Feel the spine, which runs down the middle of the back
  • Feel the top of the hips and shoulders


The ideal body condition score

  • You should be able to see and feel the outline of your cat’s ribs without excess fat covering.
  • You should be able to see and feel your cat’s waist.
  • Your cat’s waist should be clearly visible when viewed from above.


Vet treatment

What’s the treatment for obesity in cats?

Increasing activity or short-term diets alone won’t cure obesity. And tackling obesity is about more than simply reducing how much you feed your cat. That may leave them hungry or even lacking in some essential nutrients.  Keeping your cat at a safe and healthy weight is a long-term joint effort between pet health professionals and pet parents.

A safe and effective weight control programme involves:

  • Committing to long-term changes in eating habits, diet components, and lifestyle.
  • Hill’s Prescription Diet metabolic® promotes steady weight loss. It will also keep your pet feeling fuller for longer. Hills Prescription Diet r/d® is an effective alternative.
  • Probiotics to improve gut health and restore the gut biome.
  • Regular rechecks at a vet clinic for weight management support are essential
  • Keeping records of your cat’s eating habits, appearance and energy levels. Take photos.

Key facts to remember:

  • Obesity is a serious disease that won’t just disappear when the weight comes off.
  • The damaged gut biome (gut dysbiosis) and old habits will quickly re-establish without ongoing care.
  • Obesity and all the health problems associated with it will come back.
  • Monitoring and managing this disease will give your cat the best possible outlook for a longer, healthier life and a far better quality of life.


Home treatment

Home care for a cat with obesity.

Your cat’s weight clinic appointment will provide information and guidance. But the real changes happen at home.

Tackling the disease at home means:

  • Encouraging greater activity and providing mental stimulation.
  • Being careful with the type of food your cat eats, as well as their intake. Create a feeding plan.
  • Seeing your vet or weight clinic nurse for regular weight checks, once or twice per month.
  • Recording your successes, photos and records.



How can I protect my cat against obesity?

  • Feed your cat a high-quality diet that’s suitable for their age, breed, sex and lifestyle. Wet diets are less likely to cause weight gain.
  • Measure out your cat’s food accurately, avoid guessing or using scoops with dry food.
  • Give only natural high-quality treats and adjust the amount you give in a main meal if your cat’s had treats.
  • Weigh your cat every 1-3 months and act on any changes.
  • Monitor your cat’s general health and habits. Treat arthritis promptly to maintain mobility.


When to worry

When to worry about your obese cat

Obesity can trigger or worsen critical illnesses because of its wide-reaching effects on the body.

Call a vet immediately if your cat is:

  • Collapsed and unable to stand
  • Having breathing difficulties

Joii can help with:

  • Assessing your cat’s health and body condition
  • Weight clinics and expert advice with our experienced and highly-trained vet nurses.
  • Advice on managing obesity and the illnesses that contribute to it.
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