@musicfreak12
Food creates acid inside mouth and the acid level is high during meal.
This acid can wear off the tooth enamel.
So brushing teeth right after meal means attacking the tooth when it's weaken, so.. more enamel worn off.
More enamel wear off, more frail the tooth.
Saliva is the body natural way to cleanse the teeth, but it need time.
So usually it's recommended to just rinsing mouth with water right after meal
and brush teeth at least an hour after meal.