A loss of appetite can be caused by a vast range of problems in or outside the digestive tract. Causes of appetite loss include:
- Pain
- Injury
- Disease
- Fear
- Stress
- Over-eating
- Unpalatable diet
Increased Appetite - Polyphagia
An increased appetite is normal in growing puppies and kittens, pregnant or lactating females, in cold weather and when pets have increased exercise or are fed low-calorie diets. Increased appetite is also associated with the use of several drugs, particularly corticosteroids and anticonvulsants. Increased appetite is associated with a variety of medical conditions including an overactive thyroid gland (hyperthyroidism in cats), sugar diabetes (diabetes mellitus) and a variety of conditions affecting the digestive tract.