You might think that vets are obsessive about recording cats’ weights. They have good reason – sometimes gradual weight loss is the only sign of serious disease in cats. By the time a cat goes off her food or starts vomiting disease can be quite advanced.
Fur or hair ball vomits coupled with gradual weight loss indicate gastrointestinal disease. Causes of gut disease include parasites like worms and giardia. These are easy to diagnose and treat compared to other gut diseases.
Food sensitivities are uncommon but inflammatory bowel disease and bowel cancer occur relatively often in cats. Diagnosing and treating these can be quite a challenge and require much patience on the part of owner and vet.
A myriad things cause weight loss with a patchy appetite. We will nearly always order blood tests to check for kidney or liver disease, particularly in older cats.
Weight loss despite a good appetite can be due to diabetes or an overactive thyroid (hyperthyroidism). Annual check-ups and weigh-ins in cats under 10 years pick these problems up early. Cats over 10 years of age should be checked at least twice a year. With appropriate treatment affected cats go on to live long and happy lives.
Even if your cat is aiming to lose weight regular weigh-ins and veterinary supervision are essential. We want gradual loss of weight because rapid weight loss in cats can lead to liver disease.