Bodies metabolize alcohol at different rates, but a person weighing between 100 to 160 pounds becomes legally drunk after 3 or more glasses of wine, according to DrivingLaws.org. However, even after drinking 1 glass of wine, a person's judgement and motor coordination can become marginally impaired, states Brown University.
Men are able to dilute and metabolize more alcohol than women, even if they are the same size, states Brown University. Eating before drinking can slow the alcohol from reaching the small intestine where alcohol is absorbed quickly.
In the United States, drivers are considered legally drunk if they have a blood-alcohol level greater than 0.08, according to DrivingLaws.org.