Hey I Have Asked The Same Question About Purina Puppy Chow, I Still Dont Know A Lot About It But I Think That Corn Wheat And Soy Are Fillers. To My Understanding They Just Put It In There To Take Up Space And It Just Ends Up As Poop To Put It Plainly. Ur Dog Cant Use It For Anything So It Just Goes In One End And Out The Other. I Was Told To Use Nutro And Now They Say It Is Going To Be Sold At Wal Mart And For Some Reason That Makes It No Count, So It Went From One Of The Best To One Of The Worse Because It Is Going To Be Sold At Wal Mart. If U Can Buy These Foods Anywhere Aroung Nutro Is Not That Much Higher I Have Been Trying To Find A Place To Buy It Myself. Their Website Says I Have A Store About 30 Miles Away But Where I Live I Have To Go Over Mountains And Thru The Hills Take Me A Hour And A Half To Get There So Im Still Trying To Find Something Around Here. I Found One Down The Road That Sells Diamond Which Has Omega 3 In It And I Dont Know What That Is. Good Luck.