Sugar can be very harmful to your teeth, especially in large amounts. Even natural sugars in foods such as fruit can be harmful to your teeth in large and consistent doses. This is why it's important to regulate your diet and reduce your sugar intake as much as possible, to maintain the health of your teeth. Too much sugar can lead to cavities developing in your teeth and if left untreated, could potentially cause tooth loss. This is the most extreme case, however, and if you clean your teeth regularly using the proper techniques, you'll likely avoid some of the more serious cases of sugar damage.
The process behind sugar causing damage to your teeth is more in-depth than most people are aware. The sugar itself doesn't corrode your teeth, instead, it's responsible for feeding the harmful bacteria which then produces the acids that cause tooth decay. These acids then begin to corrode the teeth and can turn into harmful bacterial infections. It's these infections that essentially eat into the tooth, creating a cavity. As you can tell by the process, this isn't something that can happen instantly and if you've eaten sugary foods your teeth won't suffer these infections if you brush them properly.
The longer you leave your teeth without brushing them after eating sugary foods, however, the higher the chances are that this process has already begun and started to create harmful bacteria in your mouth. Professional advice and guidelines may be a little confusing, as dentists recommend that you wait around an hour to brush your teeth after eating sugary foods to prevent this sugar from being moved around the mouth when you brush. After an hour, the sugar is stuck to your teeth, in simple terms, meaning that when brushed, it can easily be removed from the teeth.