Scientists now believe the cause is multi-factorial and their occurrence is not solely related to the amount of alcohol consumed. Other factors include empty stomach, lack of sleep, psychosocial factors, increased physical activity while drinking, and dehydration. Persons in otherwise poor health have a greater likelihood of developing a hangover. Children of alcoholic parents report greater hangover symptoms than the children of non-alcoholics. Simply put, not drinking enough to get drunk will dramatically reduce the likelihood of hangover.
Some people believe that a hangover is nature's way of punishment to prevent future drinking.
However, studies have found that hangovers do not deter drinking. One study showed that many people with hangover, drink more alcohol to reverse its effects. The only thing that can absolutely guarantee a hangover will not occur is to avoid drinking. Most of us ignore this warning. Ladies, don't try to act macho and compete with the guys.