NutriSource Small & Medium Breed Puppy Dog Food is made with a proprietary Good 4 Life system which includes 4 key ingredients that work together to support gut health and the overall well-being of your puppy. At the core of every healthy puppy is a strong immune system and in a word, Good 4 Life represents immunity. With a focus on good gut health, Good 4 Life works to support your puppies’ health and longevity. Gut health and proper immune function are inextricably linked. Disease begins in the gut. Conversely, so does good health. Good 4 Life supports proper absorption of the nutrients that matter while helping to ensure the puppies’ body is adequately prepared to defend itself against infection and disease. Our foods work from the inside out to provide perfect end results.