A sudden, lasting increase in appetite (polyphagia) in a cat deserves attention, especially if the cat is losing weight at the same time or is older. Sometimes the cause is simple, like a new, less filling food. Sometimes it is a medical problem that is easy to treat if caught early.
Medical causes
Hyperthyroidism Very common in cats over about 10 years old. An overactive thyroid speeds up metabolism: the cat eats a lot but loses weight, and may be restless, vocal, thirsty, vomit, or have a poor coat. A blood test diagnoses it, and treatments (medication, radioactive iodine, diet) work well.
Diabetes mellitus More common in overweight, middle-aged and older cats. Signs: increased hunger, increased thirst and urination (bigger clumps in the litter, see how much water a cat should drink), and weight loss. Early treatment with insulin and diet can sometimes lead to remission.
Intestinal parasites Worms compete for nutrients, especially in kittens and cats that hunt.
Malabsorption and intestinal disease Inflammatory bowel disease, intestinal lymphoma or pancreatic insufficiency can stop nutrients from being absorbed, so the cat stays hungry. Diarrhea, vomiting or weight loss often appear too.
Medications Steroids such as prednisolone commonly increase appetite.
Non-medical causes
- Boredom, especially in indoor cats with little stimulation.
- Change of food to a less calorie-dense or less palatable one.
- Competition in multi-cat homes, where one cat eats another’s food.
- Cold weather or increased activity.
- Learned begging: cats quickly learn that meowing brings food, see can I give my cat human food.
When the appetite change needs a vet visit
- Increased appetite with weight loss: always a reason for a visit.
- Increased thirst or urination.
- Vomiting, diarrhea or changes in stool.
- An older cat with a new appetite change.
- Hyperactivity, a racing heart or a poor coat.
Your vet will weigh your cat, examine it and may run blood and urine tests. Weigh your cat at home every month or two to spot changes early.
Managing appetite at home
If the vet finds no medical cause, feed measured meals, use puzzle feeders to slow eating, offer more play, and feed cats separately if they steal from each other. If your cat is gaining weight, see how to help your cat lose weight. Regular checkups help catch problems early, see how often to take a cat to the vet.
