Cats can't taste sweetness — evolution turned off the relevant gene in their distant ancestors when they became obligate carnivores, and without working sweet receptors, a cat is as indifferent to sugar as a person is to ultraviolet light - Space Daily

Cats are notoriously indifferent to sweet things. Pour syrup near a dog and the dog will investigate. Pour syrup near a cat and the cat will ignore it. Veterinarians and cat-food companies have long noted that cats show no preference for sugar in feeding test…