Overweight Cat Health Problems | 12 Obesity Health Risks


Jul 22, 2023
Overweight Cat Health Problems | 12 Obesity Health Risks
Although this article has been written by a veterinarian and is based on scientific research and expert knowledge, it is intended for informational purposes only. It does not replace consulting your own veterinarian and establishing a patient-doctor relationship. To support our efforts, this site contains affiliate links to products we recommend and find helpful, which may earn a small commission at no extra cost to you. Read more.
Table of Contents


Over the years, there has been an increase in the number of overweight cats, and obesity is the most commonly diagnosed feline nutritional health disorder. According to the latest studies, an estimated 60% of cats in the USA (Pet Obesity Prevention), 53% of cats in the UK (PDSA), and 32% of cats in Australia (Australian Veterinary Practitioner) are overweight or obese.

Obese cats are at an increased risk of multiple health issues that can be caused by obesity or worsen due to obesity. Not only does this negatively impact your cat's quality and length of life, but many overweight cat health problems are expensive to manage and treat.

Cat Obesity - 12 Health Risks

1. Diabetes Mellitus

Diabetes is an important health issue that can occur as a result of feline obesity. Excess fat can interfere with the body's ability to use insulin effectively, so daily injections of additional insulin are required.

Insulin is a hormone released by the pancreas (an abdominal organ) that allows blood sugar (glucose) to move from the bloodstream into cells, where it can be utilized as energy. Obesity in cats leads to insulin resistance: which is when the cells don't respond well to insulin, don't uptake sugar, and the blood sugar level increases, known as diabetes. Signs of diabetes include drinking, urinating, and eating more.

Obese cats are four times more likely to develop diabetes.1 In fact, many newly diagnosed diabetic cats may go into remission (no longer require insulin injections) with weight loss, increased exercise, and an appropriate diet. Insulin sensitivity improves, and the body responds to insulin more appropriately again.

Cat Obesity - Diabetes Mellitus

2. Increased Arthritis Pain

Obese and overweight cats are twice as likely to present to the vets for early arthritis-related signs of pain, such as lameness or a stiff gait.The extra weight they carry puts stress on their joints. If a cat has arthritis, weight loss may allow for fewer pain-relief medications to be required.

Cat Obesity - Arthritis

Also, fatty tissue is not inert and creates ongoing and widespread inflammation in the body, which may worsen arthritis.

For further information on how to care for a cat with arthritis, including diagnosis, pain scoring, pain-relief options, joint support supplements, and how to improve their comfort, read The Complete Guide to Arthritis in Cats

Read the Article Arthritis in Cats - The Complete Guide to Caring for Your Cat

3. Reduced Mobility

Obese cats may be less playful and active, less able to jump and move freely, and more prone to exercise intolerance and overheating. However, a cat's activity levels will often improve with weight loss, and they will have more freedom to express their natural behaviors. 

Cat Obesity - Reduced Mobility

4. Feline Idiopathic Cystitis

Feline Idiopathic Cystitis is a condition characterized by bladder wall inflammation and difficulty urinating. For example, a cat may strain to urinate, only producing small amounts of urine, which is frequently bloody, and often outside their litter box. Cats who present with feline idiopathic cystitis are more likely to be both overweight and of a nervous disposition.3

It has also been speculated that obese cats are more prone to developing bladder stones (urolithiasis).

Cat Obesity - Cystitis

5. Constipation

Obesity is a risk factor for constipation,perhaps because cats find it challenging to posture correctly to poop or because extra fat in the abdomen affects gastrointestinal motility (movement of ingested food through the digestive tract). If a cat suffers from constipation and is overweight, weight management will be part of the treatment plan.

6. Pressure Sores

Morbidly obese cats may develop pressure sores (open wounds), particularly on their abdomen, due to their excess weight and increased amount of time spent lying down.

7. Increased Surgical Risk

Obesity is associated with an increased risk of anesthetic-related deaths in cats.5 During anesthesia, there is suppression of breathing, and overweight cats already have reduced lung function due to excess fat around their chest. Large amounts of fat in the body also affect how drugs are absorbed, distributed, broken down, and excreted, which can cause complications during surgery and recovery. Abdominal surgery is also more challenging due to the large amount of slippery fat that obscures visualization.

8. Skin and Coat Problems

Obese cats are over two times more likely to present to the vet with a skin problem1 (unrelated to allergies), such as dry flakes, an unkempt coat, or urine scalding, most likely because they cannot groom themselves adequately.

Excess fat also creates skin folds, which are warm, moist areas that promote the growth of bacteria and yeast, causing the skin inside the fold to become red and inflamed, known as skin fold dermatitis. Inflammation is worsened when the skin folds rub against each other, creating friction.

Cat Obesity - Difficulty Grooming

9. Hepatic Lipidosis

If an overweight cat suddenly stops eating, their body breaks down large amounts of fat, which accumulates in the liver and can lead to liver failure. This condition is known as hepatic lipidosis or fatty liver syndrome. Cats often present with dramatic weight loss, lethargy, vomiting, drooling, and jaundice (yellow skin), and must be taken to the vet for emergency care.

Cat Obesity - Hepatic Lipidosis

10. Spontaneous Fractures

Spontaneous fractures (not due to trauma) occurring in the top part of the thigh bone (where it connects to the hip joint) are typically seen in young, male neutered, obese cats.6

11. Impaired Breathing

Due to the extra fat around their chest, obese cats have a reduced lung volume.They are less able to take deep breaths and fully inflate their lungs, which is why overweight cats with asthma are recommended to lose weight.

Cat Obesity - Difficulty Breathing - radiographs showing excess fat around the lungs compared to a normal cat

12. Mental Health

Not only do the above health problems cause pain or discomfort, which negatively affects a cat's quality of life, but obese cats are less able to perform natural behaviors, which may reduce their level of happiness. For example, hunting, climbing, running, and grooming are all activities that cats find pleasurable, but obese cats find difficult or impossible to perform.

Cat running and climbing and enjoying life

FAQ: Obesity and Feline Health

How Can I Tell if My Cat Is Overweight?

To determine if a cat is overweight and how severely overweight they are, they need to be assigned a body condition score, which involves a visual and hands-on assessment. A cat is then given a score, with 5/9 being an ideal weight, 6/9 and 7/9 being overweight, and 8/9 and 9/9 being obese.

Ideally, your cat should be body condition scored at every vet visit, and you can ask your veterinarian to teach you the technique. Additionally, read How to Body Condition Score Your Cat for a step-by-step guide that explains how to use the Body Condition Score Chart for Cats.

Read Our Step-By-Step Guide on How to Body Condition Score Your Cat

Why Is My Cat Fat?

A cat will become overweight if they take in too much energy (calories in food) and don't expend enough energy (exercise). Over time the excess energy is stored as fat. However, this explanation overlooks the complexity and multifactorial causes of feline obesity and oversimplifies the issue. Therefore, I have compiled 14 reasons cats may become overweight, explained in the article, Why Is My Cat Fat?

Why Is My Cat Fat? Discover 14 Causes of Feline Obesity

How Can I Help My Fat Cat Lose Weight?

If your cat is overweight, read the highly effective Cat Obesity Diet Plan to help improve their quality of life and reduce obesity health risks. It consists of 5 essential steps to help your cat lose weight, as well as inspirational before and after weight loss pictures of cats, a calculator for daily treat allowance, a trouble-shooting guide (because diets can be challenging), and tips to keep your cat slim after successful weight loss.

Read our effective and safe weight loss diet plan for fat cats

Should I Take My Obese Cat to the Vet for Weight Loss?

If your cat is overweight, it is recommended to take them to a cat-friendly practice that is passionate about helping cats with their weight loss journeys.

Not only is it important to have the support of a veterinary health care team, with regular follow-ups to help maintain commitment and motivation, but usually, a veterinary prescription diet is required for safe and effective weight loss. Simply cutting back on their regular food will reduce the calories but can result in unbalanced nutrition. Therefore, veterinary prescription diets are calorie-dilute and nutrients dense to promote weight loss while preventing nutritional deficiencies. In addition, they contain adequate fiber to help your cat feel full, adequate protein to prevent muscle loss, and healthy ingredients that help support your cat's metabolism.

Veterinary Prescription Weight Loss Diets

Royal Canin Satiety

Royal Canin Satiety

Royal Canin Satiety

  • Formulated for weight loss in overweight and obese cats
  • Fiber helps cats feel full and reduces begging behavior between meals
  • Adequate protein helps maintain muscle mass
  • Ensures essential nutrient needs are met during weight loss
  • Wet and dry options are available
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Hill's Prescription Diet r/d Weight Reduction

Hill's Prescription Diet r/d Weight Reduction

Hill's r/d Weight Loss

  • Formulated for quick and healthy weight loss in just 8 weeks
  • Contains L-carnitine to help metabolize fat and maintain lean muscle
  • A blend of fibers helps your cat feel full and satisfied
  • Antioxidants to support a healthy immune system
  • Wet and dry options are available
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Hill's Prescription Metabolic

Hill's Prescription Metabolic

Hill's Metabolic

  • Formulated to help obese cats lose weight
  • Activates the metabolism and stimulates a cat's natural ability to burn fat
  • A special blend of fiber helps keep cats full between meals
  • 88% of pets lost weight at home in 2 months
  • Wet and dry options are available
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Purina Overweight Management

  • Formulated to help obese and overweight cats lose weight
  • Low in calories and fat
  • High protein helps maintain muscle mass
  • Packed with natural fiber to help cats feel full
  • Wet and dry options are available
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How Can Obesity Be Prevented in Cats?

Like all diseases, prevention is better than cure. By carefully monitoring your cat's body weight, feeding them an appropriate diet, measuring out their portion of food for the day, limiting treats, preventing food stealing in multi-cat households, and thinking of creative ways to encourage exercise and make them work for their food, we can avoid excessive weight gain. To learn more, read 10 Healthy Ways to Keep Your Cat Slim.

Discover 10 Ways to Keep Your Cat Slim and Prevent Obesity

Are Obese Cats More at Risk of Heart Disease?

Unlike humans, where there is a link between obesity and an increased risk of heart disease, a link between obesity in cats and heart disease has not been established (despite what you may read elsewhere). Although it's possible obesity may have a negative effect on heart function, heart disease in cats is normally caused by genetics, high blood pressure (due to chronic kidney disease or hyperthyroidism), or the cause is unknown.


  1. Scarlett, J.M., Donoghue, S. (1998) 'Associations between body condition and disease in cats,' J Am Vet Med Assoc, 212(11), 1725-1731.
  2. Maniaki, E. et al. (2021) ‘Associations between early neutering, obesity, outdoor access, trauma and feline degenerative joint disease’, Journal of Feline Medicine and Surgery, 23(10), pp. 965–975.
  3. Lund, H. S., Sævik, B. K., Finstad, Ø. W., Grøntvedt, E. T., Vatne, T., Eggertsdóttir, A. V. (2016) 'Risk factors for idiopathic cystitis in Norwegian cats: a matched case-control study', Journal of Feline Medicine and Surgery, 18(9), 722-729.
  4. Benjamin, S.E. and Drobatz, K.J. (2019) ‘Retrospective evaluation of risk factors and treatment outcome predictors in cats presenting to the emergency room for constipation’, Journal of Feline Medicine and Surgery, 22(2), pp. 153–160.
  5. Brodbelt, D.C. et al. (2007) ‘Risk factors for anaesthetic-related death in cats: Results from the Confidential Enquiry into Perioperative Small Animal Fatalities (CEPSAF)’, British Journal of Anaesthesia, 99(5), pp. 617–623.
  6. Lafuente, P. (2011a) ‘Young, male neutered, cat, obese, lame?’, Journal of Feline Medicine and Surgery, 13(7), pp. 498–507.
  7. García-Guasch, L. et al. (2014) ‘Pulmonary function in obese vs non-obese cats’, Journal of Feline Medicine and Surgery, 17(6), pp. 494–499.

Catastrophic Creations