1. Gastrointestinal discomfort, 2. Hair ball vomiting, 3. Discomfort caused by changing food. Cat vomiting cat food is not caused by disease. Generally, cats eating too fast or too much will cause the cat to vomit the food before it is digested. It may also be that the food fed to the cat has deteriorated, smelled, or become wet, causing gastrointestinal discomfort and then vomiting. If the breeder has recently changed the cat's food to a new one, the cat may vomit food before it has adapted.