Cat Losing Weight Despite Normal Appetite? Early Signs of Hidden Diseases

When your cat's appetite remains robust and they clean their bowl at every meal, yet their weight keeps dropping, many owners feel puzzled. In fact, "eating plenty but getting thinner" is a classic warning sign of several common feline endocrine diseases. These conditions often show no obvious symptoms in early stages, and by the time they're noticed, they may have progressed for some time. Understanding the signs of these underlying diseases can help you seek veterinary care early.

## Hyperthyroidism

Hyperthyroidism is the most common endocrine disease in cats, predominantly affecting cats over 8 years old. When the thyroid gland overproduces hormones, metabolism accelerates, causing weight loss despite increased food intake.

Common symptoms include:

* Increased appetite but weight loss
* Unusually high energy levels, tendency toward restlessness
* Increased water intake and urination
* Dull or thinning coat
* Nighttime yowling, poor sleep quality
* Rapid heartbeat

The good news is that hyperthyroidism has a high treatment success rate (approximately 83-99%), and early diagnosis and treatment can effectively control the condition.

## Diabetes

The typical presentation of diabetes is "three increases and one decrease"—increased eating, drinking, and urination, but decreasing weight. When a cat's body cannot effectively use glucose for energy, it begins consuming fat and muscle, leading to weight loss.

Warning signs to watch for:

1. Normal or increased food intake, but noticeable weight loss
2. Dramatically increased water consumption, more frequent litter box cleaning needed
3. Lethargy and increased sleeping
4. Sweet or unusual breath odor
5. Hind leg weakness, abnormal gait (neuropathy)

Obese cats are 4 times more likely to develop diabetes than cats of normal weight. If caught during the golden treatment window, approximately 20% of diabetic cats can successfully control blood sugar and potentially achieve remission.

## Other Possible Hidden Diseases

Besides hyperthyroidism and diabetes, the following conditions can also cause "good appetite but weight loss":

* **Chronic kidney disease**: Declining kidney function leads to nutrient loss, often accompanied by increased urination and dehydration
* **Intestinal parasites**: Nutrients are absorbed by parasites, preventing weight gain
* **Inflammatory bowel disease**: Affects nutrient absorption efficiency
* **Tumors or cancer**: Tumors consume large amounts of the body's nutrients

## When to Take Your Cat to the Vet

Weight changes are an important indicator of cat health. Seek veterinary care promptly in these situations:

* Weight loss exceeding 10% within a short period (weeks to a month)
* For example: A 5 kg cat losing 0.5 kg is a warning sign
* Accompanied by noticeable changes in water intake or urination
* Decreased energy or activity level
* Increased frequency of vomiting or diarrhea

It's recommended to weigh your cat regularly at home (monthly) and track weight trends. Cats over 7 years old should have health checkups every six months to help detect endocrine or metabolic problems early.

Early detection and early treatment are key to addressing unexplained weight loss in cats. Even if your cat appears to have normal energy and appetite, any continuous weight loss warrants consulting with a veterinarian.

---
**References:**
* https://heromamapet.com/blog/cat-lose-weight/
* https://peace-vet.com/feline-hyperthyroidism/
* https://www.dogcatstar.com/blog/weight-loss-in-cats/
* https://www.royalcanin.com/tw/cats/health-and-wellbeing/why-is-my-cat-losing-weight
* https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/hyperthyroidism-cats
* https://www.petmd.com/cat/conditions/digestive/c_ct_Weight_Loss_and_Cachexia

---