It’s the food, yes, but it is really the bugs that thrive in your acid foods that really do the heavy damage. A great report here, and here’s an extract to demonstrate the great stuff it contains:

It is significant to note that not all acids have an equal effect on the tooth. Acids originating from bacteria and soft drinks can initiate a carious process. Alternately, acids originating from fruit, bulimia, or gastroesophogeal reflux disorder (GERD) tend to erode only the enamel of the tooth in the oral environment.^4-7 There are other systemic factors that can amplify the acid-stimulated caries process, such as methamphetamines like crystal meth.⁸ These observations demonstrate that something more significant is happening internally beyond the oral or external acid attack. The same sugars and refined carbohydrates feeding the oral bacteria wreak havoc with the internal environment and are major factors in diabetes and obesity.⁹ Soft drinks have an insidious effect on the internal environment of the body in addition to their oral effects.¹⁰ It is because of their systemic effect that soft drinks are a contributor to not only enamel erosion but also dental caries.¹¹ Meth mouth is a dental symptom of system-wide devastation.¹²

 

And here’s a blockbuster quote that would have our fluoride favourers reeling:

Emerging evidence now demonstrates that antioxidants in green tea (epigallocatechin gallate, or EGCG) acting as MMP inhibitors are significantly more effective than sodium fluoride at preventing acid erosion.²¹