The Anorexic Cat - What Should I Do?

Introduction
Cats will often present to the veterinary surgeon with a diminished or absent appetite. Feeding is a focal interaction for owners and their cats, and anorexia can be the first sign of a number of disease processes. However, it is a non-specific sign and, as a consequence, the veterinary surgeon must consider a wide array of differential diagnoses. Significant and prolonged anorexia will lead to loss of weight and body condition. Occasionally, anorexia may be missed or underestimated by an owner, not least when the cats live with other cats, and where the cats feed communally. This may mean that the degree of weight loss evident is out of proportion to the apparent degree of anorexia.

Definitions
Anorexia describes a loss or lack of appetite, and may be partial or complete; inappetence or hyporexia describe a reduction in appetite.  [...]