Vets recommend science diet because Hills, their company, gives the vet science diet for all of their pets for free. Most vets I know have admitted this and will tell you that most grocery store brands are junk. They have also admitted that they are required to know very little about proper nutrition, or quality of ingredients. Do some research online about dog food ingredients, because if the food your feeding says meat-by-products, you could be feeding your dog euthenized shelter animals, road kill, or any number of things. But there are some quality foods that are becoming more and more available.