I am still learning about dogs (this pup is my first) but I know that my last cat lived 18 years and ate Science Diet kibble his whole life. He only received human food on very rare occassions. He was healthy until the last year of his life, when he developed kidney problems--something common in cats. Consequently, my puppy's diet is founded on a higher grade kibble with some occassional raw foods added. My mom feeds kibble and raw and she has a 12 yr old collie mix with mild arthritis that still looks great. I guess it's the old adage "all things in moderation".