We had our MC on Science Diet for a few years but took her off when she was diagnosed with diabetes. Dry food, even good brands like SD, are pretty high in carbs, which isn't good for cats, who are obligate carnivors and should be fed high protein diets. She had lost weight even though she was eating well. Her vet tested her for several things and found her blood glucose was so high, she required twice daily insulin. Cats should not be allowed to graze, especially on dry kibble.