I do the same, Pro Plan LB Puppy for the first year, then whatever Large Breed Adult food you decide is best for your dog...Purina considers 30/20 pro plan an "all life stages" food. Lots of people start a puppy on 30/20 and keep it on that it's whole life. The main purpose of a puppy blend is less calories in an attempt to keep people from having overweight puppies. I personally feed pro plan large breed puppy until they are one year old then switch to 30/20. However, as I said the main thing is don't let your puppy carry excess weight. It's the easiest and one of the most important things we need to be doing as owners.