it is tough on the teeth, pepsi and coke are as far as I can tell the worse with phosphoric acid and around 2.5 pH and on the order of stomach acid. Obviously -

it is tough on the teeth, pepsi and coke are as far as I can tell the worse with phosphoric acid and around 2.5 pH and on the order of stomach acid. Obviously -volume- counts too. however at least he's avoiding sugar which also contributes to building up a lot of plaque which is a constant supply of acid rather than a diet coke which the saliva would neutralize pH up pretty quickly back to 7