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Few studies have examined a potential correlation between obesity and cancer in cats. However, given our understanding of the risks associated with obesity, maintaining a healthy body weight is essential for the overall well-being of cats.

What causes obesity in cats?

Obesity is an excessive accumulation of body fat. At its basic level, obesity results from cats taking in more calories than they burn. Several factors may lead to obesity in cats:

    • Breed: Certain breeds such as the Manx, Norwegian Forest Cat, and Domestic Shorthair are more likely to develop obesity.
    • Diet: Free feeding or a diet consisting solely of dry food increases the likelihood of developing obesity.
    • Reproductive status: Neutering can cause an increased interest in food, which may lead to obesity.
    • Exercise: Indoor cats with little physical activity are more likely to become overweight.


How do I know if my cat is obese?

In cats, vets usually monitor the body fat percentage using the Body Condition Score (BCS). BCS evaluates several physical features, including the shape of the cat when viewed from above or from the side and how easily palpable the ribs are. The vet scores these features on a 9-point scale, with 1 representing an emaciated cat, 5 being ideal, and 9 representing a severely obese cat.

What is the relationship between obesity and cancer?

Although data is currently limited, some reports show that obese cats may have an increased cancer risk. In humans, increasing evidence suggests that a high percentage of body fat increases the risk of developing different types of cancer, including pancreatic, liver, breast, and ovarian cancer, among others. While there is a lack of similar studies on cats, the same association may exist between obesity and cat cancer. Therefore, the need to investigate this relationship with our feline companions is clear.

How might obesity lead to cancer in cats?

Fat (adipose tissue) in humans and cats releases molecules called adipokines and various hormones. For humans, these secretions increase cancer risk in the following ways:

    • Adipose tissue produces excess amounts of the sex hormone estrogen, which increases the risk of breast, endometrial, ovarian, and other cancers.
    • Adipokines promote cell growth leading to cancer.
    • Excess adipose tissue may lead to inflammation. Over time, inflammation can damage the cell’s DNA and subsequently generate mutations that alter cell growth and development, ultimately leading to cancer.

Obesity leads to increased levels of the hormones, insulin and insulin-like growth factor in the blood. These hormones promote cell growth and proliferation, leading to the development of endometrial, colon, and pancreatic cancer.

Since obese cats release similar hormones to humans, obesity-related hormones may influence cancer development in cats, but there is a need for more research.

How do I keep my cat at a healthy weight?

A balanced diet combined with regular exercise is the best way to prevent your cat from becoming obese. The following suggestions can help you keep your cat at a healthy weight:

    • Ask your vet to help you choose the most suitable food for your cat and determine the appropriate portion size. Kittens, adults, and senior cats all have different nutritional requirements. Cats with medical concerns may also require a specialized diet.
    • Maintain a regular feeding schedule. Avoid free feeding as this can often lead to overeating.
    • Make sure your cat gets enough daily exercise outdoors or indoors using toys, feeding puzzles, and walks.
    • Have a vet assess your cat’s body condition score during each visit. If your cat is overweight, the vet can help you set a target weight and develop a specialized diet and exercise plan.


How do I help my cat lose weight?

If your cat is overweight or obese, diet and exercise are the simplest and most effective ways to reach a healthy weight. Using the following tips may help your cat lose weight:

    • Ask your vet for the most appropriate food and feeding plan to help your cat lose weight, including a specialized, low-calorie, nutrient-rich diet. It is important not to starve your cat, as this can lead to excessive protein loss and adverse health effects.
    • With a specialized diet, exercise can help promote fat loss while preserving lean muscle tissue. You can fit most cats with a harness and teach them to walk on a leash. Alternative indoor exercises can include the use of cat toys and feeding puzzles.
    • Schedule regular weigh-in sessions with your vet to track your cat’s weight and body condition. Your vet can then identify trends and determine if there are any needed adjustments to feeding or exercise.



Helping your feline companion maintain a healthy body weight through diet and exercise can provide many health benefits to living a happy and healthy life. Staying up to date on research examining the relationship between cancer and obesity in cats will also help keep your cat healthy.

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Last Updated: June 23, 2022

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The following sources were referenced to write the content on this page:

Burkholder, WJ 2000, ‘Use of body condition scores in clinical assessment of the provision of optimal nutrition’, J Am Vet Med Assoc, vol. 217, no. 5, pp. 650-654.

Calle, EE & Kaaks, R 2004, ‘Overweight, obesity and cancer: epidemiological evidence and proposed mechanisms’, Nat Rev Cancer, vol. 4, no. 8, pp. 579-591.

Cave, NJ, Allan, FJ, Schokkenbroek, SL, Metekohy, CAM & Pfeiffer, DU 2012, ‘A cross-sectional study to compare changes in the prevalence and risk factors for feline obesity between 1993 and 2007 in New Zealand’, Prev Vet Med, vol. 107, no. 1-2, pp. 121-133.

Colliard, L, Paragon, BM, Memuet, B, Bénet, JJ & Blanchard, G 2009, ‘Prevalence and risk factors of obesitu in an urban population of healthy cats’, J Feline Med Surg, vol. 11, no. 2, pp.135-140.

Corbee, RJ 2014, ‘Obesity in show cats’, J Anim Physiol Anim Nutr, vol. 98. No. 6, pp. 1075-1080.

Courcier, EA, Mellor, DJ, Pendlebury, E, Evans, C & Yam, PS 2012, ‘An investigation into the epidemiology of feline obesity in Great Britain: results of a cross-sectional study of 47 companion animal practises’, Vet Rec

Courcier, EA, O’Higgins, R, Mellor, DJ & Yam, PS 2010, ‘Prevalence and risk factors for feline obesity in a first opinion practice in Glasgow, Scotland’, J Feline Med Surg, vol. 12, no. 10, pp. 746-753.

Fettman, MJ, Stanton, CA, Banks, LL, Hamar, DW, Johnson, DE, Hegstad, RL & Johnston, S 1997, ‘Effects of neutering on bodyweight, metabolic rate and glucose tolerance of domestic cats’, Res Vet Sci, vol. 62, no. 2, pp. 131-136.

German, AJ 2006, ‘The growing problem of obesity in dogs and cats’, J Nutr, vol 136, no. 7, pp. 1940s-1946s.

Ish-Shalom, D, Christoffersen, CT, Vorwerk, P, Sacerdoti-Sierra, N, Shymko, RM, Naor, D & De Meyts, P 1997, ‘Mitogenic properties of insulin and insulin analogues mediated by the insulin receptor’, Diabetologia, vol. 40, no. 2, pp. S25-S31.

Iyengar, P, Combs, TP, Shah, SJ, Gouon-Evans, V, Pollard, JW, Albanese, C, Flanagan, L, Tenniswood, MP, Guha, C, Lisanti, MP, Pestell, RG & Scherer, PE 2003, ‘Adipocyte-secreted factors synergistically promote mammary tumorigenesis through induction of anti-apoptotic transcriptional programs and proto-oncogene stabilization’, Oncogene, vol. 22, no. 41, pp. 6408-6423.

Kienzle, E & Bergler, R 2006, ‘Human-animal relationship of owners of normal and overweight cats’, J Nutr, vol. 136, no. Suppl7, pp. 1947S-1950S.

Laflamme, D 1997, ‘Development and validation of a body condition score system for cats: a clinical tool’, Feline Pract, vol. 25, pp. 13-18.

Lauby-Secretan, B, Scoccianti, C, Loomis, D, Grosse, Y, Bianchini, F & Straif, K 2016, ‘Body fatness and cancer—viewpoint of the IARC working group’,
N Engl J Med, vol. 375, no. 8, pp. 794-798.

Lund, EM, Armstrong, PJ, Kirk, CA & Klausner, JS 2006, ‘Prevalence and risk factors for obesity in adult dogs from private US veterinary practices’, Intern J Appl Res Vet Med, vol. 4, no. 2, pp. 17-187.

Radin, MJ, Sharkey, LC & Holycross, BJ 2009, ‘Adipokines: a review of biological and analytical principles and an update in dogs, cats, and horses’, Vet Clin Pathol, vol. 38, no. 2, pp. 136-156.

Rowe, E, Browne, W, Casey, R, Gruffydd-Jones, T & Murray, J 2015, ‘Risk factors identified for owner-reported feline obesity at around one year of age: dry diet and indoor lifestyle’, Prev Vet Med, vol. 121, no. 3-4, pp. 273-281.

Tchernof, A & Després, JP 2000, ‘Sex steroid hormones, sex hormone-binding globulin, and obesity in men and women’, Horm Metab Res, vol. 32, no. 11-12, pp. 526-536.

Teng KT, McGreevy PD, Toribio JALML, Raubenheimer D, Kendall K & Dhand NK 2018, ‘Associations of body condition score with health conditions related to overweight and obesity in cats’, J Small Anim Pract, vol. 59, pp. 603-616.

Zhang, H, Xie, C, Spencer, HJ, Zuo, C, Higuchi, M, Ranganathan, G, Kern, PA, Chou, MW, Huang, Q, Szczesny, B, Mitra, S, Watson, AJ, Margison, GP & Fan C_Y 2011, ‘Obesity and hepatosteatosis in mice with enhanced oxidative DNA damage processing in mitochondria’, Am J Pathol, vol. 178, no. 4, pp. 1715-1727.

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