pH is basically -ve logarithm of H+ or OH- ions. H+ increase shows increase in acidity while OH- ions increase shows increase in basic value. Our body can only digest in the presence of acid. Gastric acid is produced in stomach, Hydrochloric Acid is main component of this acid. When we drink anything bitter or eat it like coke, pepsi etc. Acid is provided through these. However we get acid from another source than the natural. But the problem begins here.
One of them is, our stomach will also produce acid and acid increases in our body, that will cause burning conditions in stomach.
Other problem will lead our stomach to incapable to produce acid and then whenever we dont use acidic things in our diet, than we will face the digestion problems.
Credits: Burger King
My point is that dont make it habbit to take always an acidic thing to eat or drink everytime during the meal and also eat as much as your body requires not your mind.