I've posted this before, but I went from growing up in a place with fluoride and having 1 cavity, to moving to a place as an adult that didn't.
Within a couple years, I had like 8 cavities and a root canal and it didn't stop there.
I didn't change anything else.
My oral hygiene habits were obviously not good, and I've finally got it better under control, but the change was dramatic.
And I was never a sugary drink person either.