well, i have not finished reading Prices book yet, tho i am making good headway and it fascinating to say the least.
but as i understand Price, he belived that there are two critical factors in the diet - minerals and plenty of the fat soluable "mineral activators" by which he mostly meant Vit A and D, and also 'activator X' which is a concept i don't want to get into in this post (mainly because i don't yet fully understand it)
so, according to Price, if a person is getting plenty of minerals and plenty of mineral activators, then the ph level can be maintained quite easily. thus a person may eat liver (an "acid" producing food), and it creates an acidic reaction in the body, HOWEVER the liver is so full of vit A and D and other minerals, that the OVERALL impact is to provide the person's body with all the raw material it needs to maintain ph balance, and in that instance its easy to do so.
my comment - however, if those factors are missing, then you may need pay close attention to the diet and choose foods carefully in order to maintian ph.
i think Price was saying the ph is easy to maintain IF the person is eating a diet close to what he called the true primitive diet. this is my understanding of Price's work so far. i could be off a bit tho.