Oooh it’s even cooler than that!! You’re spot on, acid is the problem. And acid from food, candy, coffee, etc. is harmful for enamel for sure.

But sugary stuff that isn’t acidic also rots teeth. Why? Because the bacteria in your mouth do what’s called lactic acid fermentation. Basically, when they take a sugar molecule and want to make “usable” energy out of it (in the form of something called ATP, or adenosine triphosphate), they end up creating lactic acid as a byproduct. In essence, the stuff living in your mouth makes acid out of sugar.

We also need to break sugar down into ATP, but we do something called cellular respiration instead. It uses oxygen and creates CO2 as a byproduct! That’s why we need oxygen to breathe, and why we breathe out carbon dioxide. But, when you work your muscles hard (lifting weights, sprinting), you might use the ATP in your muscles faster than your body can make it with cellular respiration. In that case, your cells will also do lactic acid fermentation! That’s what we’re feeling when we “feel the burn” (well, that and micro-tears in the muscle, in some cases).

Source: I’m a biologist! And I love sharing weird facts like this! Thank you for the excuse to write this out :-)