You did not say how old your puppy was, but the thing with the formula is a myth there is no reason do do that. On your food I would say an all stages food or to compare the label of your puppy food to a large breed puppy and check the protein amounts. As Southern said the Large breed is designed to slow down the growth by formulating them with less protein and fat. Looking at the list for Ultra Puppy it is 30% Protein and the Large breed puppy is 32% so that is really not alot of difference either way.