You can find so much nonsense about dog food that you really need to learn first some nutrition fundamentals to be able to separate the rights from the wrongs. The right puppy food certainly is the dog's life extender No 1, so important food is for both health and behavior!
Now you may still be thinking in terms of dog food brands. Yet industrial dog food is nothing but marketing. Industrial "dog food" is a waste product from rendering plants! When you buy "premium brand dry kibble" you don't buy dog food, you buy marketing: When you spend an average $4.03 per pound or $8.88 per kilo on "premium brand dry kibble", the "food" input cost is a mere $0.20, while $8.68 per kilo are the cost of marketing that kind of "food". The cost of "teaching" budding veterinarians and ordinary dog owners that our human foods would be "bad for dogs".
Quite the contrary: Unless you eat fast food 24*7*365(?), there is nothing worse than to feed your dog industrial pet food! Yes, there may be a few commercial products that are okay to feed your dog once a while without risking costly long-term health issues, but note that kibble and tins always are industrial crap, not dog food.
The few commercial dog foods that aren't industrially produced all cost multiples of what human foods cost! And NO commercial dog food fed regularly is as healthy and safe as REAL foods are (human foods). We are not talking here of crisps and sweets etc. But natural homemade foods.
Simply put: Today's domesticated dogs only even exist because dogs developed as scavengers of human food leftovers! For some 30,000 years it has been that way. And only since about the 1950ies, some clever marketing people from the blossoming pet "food" industry started to successfully brain-wash average ordinary vets and dog owners into believing: "No!! Human foods are bad for dogs!"
Therefore our MYGERMANSHEPHERD PERIODICAL also helps to understand the nutrition fundamentals one needs to know to be able to separate the rights from the wrongs. If you are willing to learn something new(?), you may subscribe for free here. Obviously the Periodicals cannot and don't intend to teach all that one can learn from our Top nutrition expert in the Dog Expert Interview Series. However, naturally a lot of that insight got incorporated in the New Puppy Diary, and all relevant Periodicals are linked in the New Puppy Diary as well.
Note that every key point raised above you can find more comprehensively explained in other places on this website. The menu is your friend. Here, links have been omitted only to keep this decision tree straightforward.
PLEASE NOTE: Posting a fragment of your overall dog problem in the comments below is not going to help. Provide complete details if you really seek the right solution. Of course we have a page for that as well: Dog Problem Consultation.