A puppy eats a lot of food. From birth up to six months of age, he'll need to eat two to four times as much as an adult dog to support all that growth. A good rule of thumb (paw?) is that after his first week of life, when his weight doubles from what it was at birth, a puppy should gain one to two grams per pound of anticipated adult weight each day. This means that if your German Shepherd puppy weighs 75 pounds as an adult, he should gain three to five ounces per day as a puppy.
here are some guidelines:
hope this helps.