Sometimes younger German Shepherds require a high-energy diet to keep them active. This is the case with the dogs that live both indoors and outdoors. These dogs also require a diet rich in protein to regulate their body temperature. German Shepherds Puppy food needs a minimum of 22% of protein for their growth while adult dogs need a maintenance protein of 18%. They also need8% of fats for puppies and 5% for adults to support their energy requirements.