Keep in mind that dry foods are not refrigerated and they sit in warm warehouses, on pet store shelves, and in your cupboards for weeks or months before your pets consume them. Fats can easily become rancid, and bacteria will proliferate, in this type of environment. There is no doubt that dry food is responsible for far more intestinal problems, and other diseases, than most veterinarians and cat owners realize. The three key negative issues associated with dry food are:

1) water content is too low
2) carbohydrate load is too high
3) type of protein – too high in plant-based versus animal-based proteins

Source: Catinfo