Every time you eat or drink anything sugary, your teeth are under acid attack for about one hour. This is because the sugar will react with bacteria in plaque (sticky coating on your teeth) and produce harmful acids. So it is important to cut down on how often you have sugary foods, which will limit the amount of time your teeth are at risk.Acidic foods and drinks can be just as harmful to your teeth. The acid wears away the enamel, and will leave the dentine uncovered. This is called dental erosion and makes your teeth sensitive and less attractive.A diet rich in vitamins, minerals, fresh fruits and vegetables can help to prevent gum disease. Gum disease can lead to tooth loss and cause bad breath.

Some foods and drinks are more acidic than others and some are acidic enough to attack your teeth directly. Every time you eat or drink anything acidic your teeth becomes softer for a short while. If this happens too often your mouth does not have a chance to repair itself. Over time you start to loose enamel of your teeth.
To help prevent this you can:
Limit acidic products and fizzy drinks to meal times to reduce the number of acid attacks on your teeth.
Drinks should be drunk quickly without swishing around your mouth. Or use a straw to help drinks go to the back of your mouth and avoid long contact with your teeth.
Wait for at least one hour after eating or drinking anything acidic before brushing. This gives your teeth time to build up their mineral content again.

The main point to remember is that it is not the amount of sugar you eat or drink, but how often you do it. Sweet foods are allowed, but it is important to keep them to mealtimes.To help reduce tooth decay, cut down on how often you have sugary foods .
Chewing gums containing xylitol may help reduce tooth decay.

Brush teeth after meal
Eating and drinking naturally weakens the enamel on your teeth, and brushing straight afterwards can cause tiny particles of enamel to be brushed away. It is best not to brush at least one hour after eating.
Chewing gum helps your mouth produce more saliva, which helps to cancel out the acid in your mouth after eating or drinking. It has been proven that using sugar free chewing gum after meals can prevent tooth decay. However it is important to use only sugar free gum, as ordinarily chewing gum contains sugar and therefore may damage your teeth.