1st Choice Sterilized is a complete food for adult cats from 1 year up and it is specifically formulated for spayed or neutered cats. Effective use of a special diet provides immediate help to address your cat's catheter needs after surgery and beyond. 1st Choice Sterilized is a chicken, grain free formula that promotes digestion and sources of alternative fibers help sense satiety and maintain good bowel function. Chicken meat is the main source of protein and has been thought of with high levels of protein to help maintain muscle mass without fattening your cat. Additionally, specific supplements favor fat metabolism and help maintain weight, with the addition of low levels of magnesium help prevent complications in the urinary tract while maintaining a balanced pH.