It is not normal for an adult pet cat to spend most of its waking hours eating. Most cats have appetites that are easily sated; pet cats can go days without eating just because they do not seem to be hungry. However, if a cat is constantly eating and begs for more food, the cat needs to go to a vet to determine the cause.
All cats have different appetites due to size, health and the amount of exercise they get. A cat living outdoors in all weather will usually need more calories as compared to a cat living in a temperature-controlled home. Kittens will also need more calories in order to help their bodies grow. A cat owner needs to be familiar with how much a cat normally eats in order to determine if there has been a marked increase in appetite.
Female unspayed cats will become obsessed with eating because they need to increase calories to help their kittens grow. Pregnant cats may have a marked increase in appetite before they begin to show physical signs of pregnancy. The pregnant cat may eat far faster than normal, and may become aggressive if someone tries to take the food away. One to two weeks before giving birth, the appetite will drop, according to "Cat Owner's Home Veterinary Handbook."
Several serious health problems can cause a sharp increase in a cat's appetite. These include hyperthyroidism, or overactivity of the thyroid gland; diabetes, where the cat eats and drinks more because of low blood-sugar levels; Cushing's syndrome, a problem of the adrenal glands; liver tumours, which can be cancerous; and digestive problems such as inflammatory bowel disease. Most of these can kill a cat if left untreated, but all are treatable, especially if caught early.
Some medications may cause a large increase in appetite in some cats, according to veterinarian Douglas Brum. These drugs include all corticosteroids like prednisone, betamethasone and hydrocortone. Other appetite-increasing drugs include the antidepressant fluoxetine (Prozac) and phenobarbitol, used to control seizures. If a cat is on a new medication and has an increase in appetite, notify a veterinarian.
One of the signs of dementia in very old cats is a marked change in appetite, including demanding to be fed at times when the cat is normally sleeping. Other signs of cognitive dysfunction in older cats are urinary or fecal incontinence, not recognising family members, vocalising far more often than usual and problems walking.