Diabetes mellitus is a disease that causes your cat to either have an absolute shortage of insulin (Type I), or an incorrect response from the cells to the insulin that is being produced (Type II). Both of these conditions will prevent your cat’s muscles and organs from converting glucose to energy, and will result in excessive amounts of glucose in the blood (hyperglycemia). Increased appetite and thirst are among the most common signs associated with diabetes in cats.
Hyperthyroidism is a disease caused by overproduction of thyroxine, a thyroid hormone. Normally thyroid hormones increase chemical processes occurring within the cells of your pet’s body. However, in hyperthyroidism, the excessive hormone levels push the cells and body into overdrive, resulting in increased metabolism and often increased appetite.
Hungry cat? It may be possible that your cat is not properly absorbing the nutrients of his food due to a gastrointestinal problem such as Inflammatory Bowel Disease (IBD). This in turn often leads to weight loss and increased appetite, among other things. IBD can affect cats at any age but is more common in middle-aged and older cats.
There are several types of gastrointestinal cancers that can afflict your cat’s stomach and intestines with tumors, including adenocarcinoma and leiomyosarcoma. Many of these types of cancer will cause increased appetite in your cat due to the malabsoption of food.
As your cat gets older she may undergo behavioral or physical problems — such as the diseases already discussed here — which in turn can cause issues such as increased appetite.
It’s important to visit a veterinarian if your cat ever undergoes an unexpected change in behavior. They can help identify the underlying cause and hopefully treat it. In the case of a sudden increase in appetite, you will want to ask your veterinarian if a change in diet is also required. There may be a therapeutic diet that may help your pet’s condition as well as caloric intake to consider.