1. Canned Fruit Thought that canned peaches were a healthy alternative to pudding? Wrong. Canned fruit is full of delicious, destructive sugar. Excess sugar is kryptonite to your teeth. It sticks to your teeth providing all sorts of tasty nourishment for the bacteria, which lives in your mouth to thrive on. The more sugar, the more bacteria, the more plaque the bacteria creates and the higher your chances of gum disease, cavities and general oral nastiness. Canned fruit is a double whammy because it not only contains ladles of sugar, it also contains acidic fruit. You may be familiar with the old adage ‘an apple a day keeps the doctor away’, well, it won’t stop you from paying a dentist a visit. The acid in fruit can be extremely damaging to the enamel of your teeth which weakens them and which can cause staining and discoloration.