If you look at the analysis between an adult food (say Chicken soup adult formula) and a large breed specific food (Eagle Pac large and giant breed puppy food) you will find that there is actually less protein, fat, etc. in the large breed forumula because they don't need high protein or extras that are in regular puppy food. If you pick a good food you shouldn't have to feed your large breed dog puppy or size specific food. For example... Chicken soups adult forumla analysis: Guaranteed Analysis: Crude Protein 24 Crude Fat 14 Moisture 10 Crude Fiber 3 Omega-6 Fatty Acids (min) 2.2 Omega-3 Fatty Acids (min) 0.4 Sodium 0.3 Now Eagle Pac large and giant breed puppy food: Guaranteed Analysis: Crude Protein min. 23 Crude Fat min. 12 Moisture max. 10 Crude Fiber max. 3.5 The only difference is that the giant/large breed forumla has LESS protein, fat, and fiber, because you don't want growth spurts like you get with regular puppy food. Chicken soup adult forumla will be perfect for Gunnar with everything he needs. So I guess my point is that he is not missing any nutrients by eating an adult forumla, he is actually gaining some nutrients.