What is the best food for my 4 years old pitbull?

My pitbull name is Alex and he is 4 years old. He is in a pretty good condition but I am searching for some dog food wich will really make him strong. I read here http://mysweetpuppy.net/best-dog-food-for-pitbulls/ that earthborn holistic is a great choice and I don't mind it because it is expensive.

I believe in the US made products but still, I am not sure if that is my best option.

My dog has always been fed with US brands like Nulo, Wildlife and etc. And I always fed him from time to time with the raw diet or homemade food.

But he never became really bulky and strong which I wanted for him. Do you think that earthborn is a good brand to try out or do you have some other suggestion for me? Thank you!!