If you must have sugary drinks then use a straw. This lowers the amount of sugar that reaches the tooth surface.
Tea, especially green tea, seems to be good for teeth. But it contains stimulating caffeine, so avoid late night consumption.
Rinse after eating citrus fruit. It is very healthy, but the acidic content is hard on teeth.
There is a diet trend that recommends lemon water or apple cider vinegar drinks. These may have health benefits, but they are hard on teeth. Rinse afterward.
Cashew nuts contain some compounds that benefits teeth, with no real drawback other than the calorie content.
The basic content of chocolate, the cocoa or raw cacao, is good for teeth and our health in general. It is only the sugar that causes decay. Find chocolate with high cocoa/cacao and little or no sugar. 70% coco is ideal, though it is a stimulant.
Eat crunchy salads, fruits and vegetables. These clean teeth, and have other heathy benefits.
Sugar is bad for teeth even if it bypasses our mouth. Just having it in our body’s system seems to cause problems; it circulates and feeds bacteria. Individuals with better circulation inside their teeth suffer far fewer effects.