Q: Which foods promote cavities most? Which help prevent them?
A: The bacteria in your mouth thrive on carbohydrates, especially sugars. So cut down on foods containing added sugars, especially those that stick to teeth. Sugary beverages are particularly harmful if you sip them, since that keeps teeth bathed in sugar.
Starchy foods contain carbohydrates that are partly converted to sugars in the mouth; these are most “cariogenic” when, like cookies and cakes, they also contain sugars and tend to adhere to teeth. Frequent snacking on cariogenic foods, in particular, promotes tooth decay because it keeps teeth constantly under attack.
In contrast, foods such as cheese, milk, plain yogurt, calcium-fortified tofu, leafy greens, and almonds may benefit teeth thanks to their high amounts of calcium and other nutrients. Fruits and vegetables are high in water and also stimulate saliva production. So if you do snack, choose fruit, veggies, or a piece of cheese.
Also see Fluoride Treatments: Do or Don't?