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Feline Obesity


What is feline obesity?

The ancestors of our cuddly cats hunted day and night to feed themselves. No comfortable beds, food deliveries or treats for them! Our privileged pets are far less active, roaming and hunting less. As a result, 30-40% of pet cats in the UK are overweight.


Cats are overweight when they are 10% over their lean body weight and obese when they are 20% heavier. When you see your cat every day, it is difficult to notice excess weight creeping on. Regular veterinary checks help as we can weigh your cat and be alert to any upward trends. Body condition scoring is a helpful tool. We can teach you to assess weight in this way, focussing more on your individual cat’s body shape to determine their ideal weight.


Feline obesity is rarely caused by a medical condition, but it is possible if your cat is gaining weight without overeating. Underactive thyroid disease and a hormone disease called hyperadrenocorticism are possible culprits, although these are uncommon in cats. Pregnancy always needs to be considered in an entire queen. Unfortunately, some conditions cause fluid accumulation in the abdomen, which can appear as weight gain. Diseases such as heart disease, lung disease and arthritis can slow your cat down, reducing their activity levels, so weight gain occurs despite them eating normally. A veterinary examination can identify these problems in your cat.

Which cats are at risk?

Obesity is more likely to occur in middle-age, growing cats are unlikely to accumulate excess body fat. Similarly, elderly cats are more likely to lose weight.


Neutering has multiple health benefits, meaning that our cats live longer. They roam and fight less, meaning they are safer – but also that they’re less active. Neutered male cats are most likely to become obese, so be extra-careful with portion control.


Indoor cats are often less active and may overeat through boredom. Single cats are more likely to be obese than those who share their homes with other animals. Interestingly, oriental breeds (such as Siamese and Abyssinian cats) are less likely to become obese than moggies.


Cats often gain weight if they take certain long-term medications. Corticosteroids and hormone treatments can have this effect.


Stress can cause cats to overeat too. Their environment is a vitally important factor – difficult inter-cat relationships can cause stress, as can another cat invading their territory. Even changes to the environment (such as moving furniture, or working from home) can unsettle a cat who’s used to things being just so!


Obese cats have been found to be resistant to leptin, the hormone which signals when they are full. These cats will overeat if free fed i.e. if food is left down for them. Currently, we cannot identify which cats will be leptin resistant, but free feeding of overweight cats is likely to result in a worsening waistline.

Why does feline obesity matter?

Obesity can have severe effects on a cat’s health. An overweight middle-aged cat is 2.7 times more likely to die than a cat with a healthy bodyweight. Obese cats are predisposed to several serious diseases:


Diabetes is caused by lack of insulin, or insulin resistance. Obese cats are less sensitive to insulin. This results in high levels of glucose in the bloodstream (hyperglycaemia). Hyperglycaemia causes lethargy, excessive drinking and urination, weight loss, cataract formation, high blood pressure and liver disease, making the cat very unwell. Visit us if you have any concerns about diabetes in your cat- a simple blood sugar test and urine test can identify it. If diabetes is managed quickly, your cat can achieve remission, meaning that they will not require insulin in the long-term.


Joint disease is caused and exacerbated by obesity. Increased wear and tear damages the cushioning cartilage inside the joints. This causes osteoarthritis, as the bone ends become inflamed and movement becomes painful. You may notice that your cat becomes less active and adventurous. We can diagnose osteoarthritis and advise you on successful management.


Hepatic lipidosis is a serious liver disease seen in overweight cats. If an overweight cat stops eating the liver attempts to mobilise fat stores. The triglyceride fats released damage the liver, causing liver failure. Anorexia may be caused by being accidentally shut in somewhere, stress, or another condition making them feel unwell. It is important to be vigilant when overweight cats stop eating as this disease can be fatal.


Obese cats with low activity levels are more likely to develop cystitis and bladder stones as they move around and urinate less frequently.


Studies have shown that obese cats have mild bone marrow suppression. This makes their immune system less effective.


Obesity can exacerbate conditions such as heart disease and asthma, as the heart and lungs need to work harder. Cats are exceptionally good at hiding disease so regular health checks with chest auscultation can give you peace of mind that their heart and lungs are healthy.


Skin chafing and infection can occur around skin rolls or the inner thighs of overweight cats. These areas need to be regularly checked for any signs of inflammation and infection.


Finally, obesity can increase the risk of anaesthesia and surgical management of other conditions. Both anaesthesia and surgery are generally safe, but the extra strain on the heart and lungs and increased surgical time because of increased bodyweight can complicate treatments.

How to treat feline obesity?


Weight reduction involves increasing activity and reducing calorie intake. Although this sounds simple…………. it often isn’t! We can help by recommending an effective weight loss diet and how much to feed. Weight checks allow us to weigh and condition score your cat regularly, to adjust the ration as necessary. A gradual weight loss regime is best as abrupt changes can affect your cat’s intestines and liver. Increasing their activity levels by playing with your cat will aid weight loss. Cats in the wild hunt and eat 8-10 mice or similar sized small mammals every day. We can save our local wildlife and manage your cat’s weight by feeding them in a similar way. Small, frequent meals with hunting activity will prevent boredom and slow them down, allowing more time for them to feel full.

We have developed the ultimate tool to feed your cat in a natural way. The puzzle feeder provides mental stimulation akin to hunting as they work to catch the kibble. 10-15 pieces of most recommended kibble will deliver the same number of calories as a mouse, so portion control is simple. Your cat will enjoy the challenge of hunting their food around the shaped base. Using this food bowl will enliven your cat’s mealtime, making it fun and fighting boredom. The feeder is made of bamboo rather than plastic to protect the environment and can be viewed here.



Feline obesity can be successfully managed so your cat can have a healthy, happy life. Working together, we can ensure that your cat can maintain a healthy bodyweight. This will protect them against serious illness and painful joints and improve their quality of life.


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