Maximum dental association recommends to brush your teeth twice a day but we should know that if you snack and drink throughout the day, it may be helpful to brush your teeth more often.  Brushing teeth helps to remve the plaque that causes from food and dangerous for enamel. The bacteria in plaque causes the two major tooth-related diseases, cavities (dental caries) and gum disease (periodontitis). So It's important to brush your teeth after you eat.