Certain foods and drinks - especially those high in carbohydrates and sugars - encourage the creation of specific bacteria in your mouth that attack your tooth enamel for at least twenty minutes following a meal or a snack. By brushing your teeth right after you eat, you will be discarding of the bacteria before they attack your tooth enamel.
For optimal results, you should use an ADA-accepted fluoride toothpaste, which contains fluoride. This helps to prevent tooth decay, triclosan and to reduce plaque and gingivitis. This double-combo acts to get rid of plaque and prevent tooth decay, ensuring that your teeth are squeaky clean after a meal.
However, you should know that brushing after each meal could affect your tooth enamel. According to the Mayo Clinic, you should wait a minimum of 30min before brushing your teeth after consuming anything acidic. Foods containing citric acid (oranges, grapefruits and lemons etc.), weaken your tooth enamel. If you brush your teeth right after consuming something acidic, you could potentially damage the enamel in its weakened state.
Consequently, it's a better idea to brush your teeth prior to eating anything acidic and follow that up by drinking a glass of water which help washes away the acids. There is an alternative to waiting to brush your teeth after eating something acidic. You can try eating nutrient-rich foods that are low in carbohydrates and sugar. This helps decrease the harmful effects that the acidic foods can create.
Lastly, according to the American Dental Association, prolonged exposure to phosphoric acid can erode hard tissues from the tooth surface. Phosphoric acid is found in soft drinks like soda and diet soda. Acid erosion can cause permanent damage to your teeth. You should be cautious with the amount of soft drinks and sugary foods that you consume and also try to limit snacking in between meals.