Some foods are obviously bad news. Soda, candy bars, cupcakes -- we all know they're going to wreak havoc on our systems. Others can be great for your body but not so great for your mouth. Dark-colored fruits, for example, can cause plaque and stain teeth due to their high sugar and acid content (although natural sugar is much less damaging than refined sugar). Veggies, though, are all-around amazing. They're low in sugar and acid, so they won't cause plaque or stains, and if they're crunchy, the chewing motion will physically brush your teeth -- and produce helpful saliva, which is your body's natural plaque fighter.