Controlled drinking can be difficult if you're not sure what a "drink" is. Just like Americans have a hard time knowing what 1 serving of their favorite Ben and Jerry's ice cream is (a half-cup or 1/4 of a pint), we also have a hard time knowing what is a serving of alcohol is.
Go to this link at the National Institute of Health (NIH) and learn more about what constitutes just one drink of alcohol. According to the NIH, lower risk drinking would be for men no more than 4 drinks on any single day AND no more than 14 drinks per week; for women, no more than 3 drinks on any single day AND no more than 7 drinks per week.
To stay at low risk for alcohol use disorders, you must keep withinboth the single-day and weekly limits.