Drinking lighter colored drinks isn't a good way to prevent a hangover, but it may help a little. In addition to alcohol, compounds linked to a hangover from alcoholic drinks include chemicals called congeners, which result from the fermenting process. Congeners give many types of alcoholic beverages their flavor and can contribute to hangovers or worsen their severity.

Congeners are found in larger amounts in dark liquors, such as brandy, bourbon, darker beer and red wine, than they are in clear liquors, such as vodka, gin and lighter beers. One particular congener — methanol — breaks down into the toxins formaldehyde and formic acid, which can worsen a hangover.

While lighter colored drinks may slightly help to prevent a hangover, drinking too many alcoholic beverages of any color will still make you feel bad the morning after. Drinking large amounts of alcohol can cause dehydration, low blood sugar, digestive irritation and disturbed sleep — all factors that lead to hangover symptoms.

In several studies, no effective method of hangover prevention was found. The only sure way to prevent a hangover is to drink in moderation or not drink at all. For healthy adults, moderate drinking means up to one drink a day for women of all ages and men older than 65, and up to two drinks a day for men 65 or younger. Women who are or may be pregnant should not drink at all.

One drink is defined as:

• 12 ounces (355 milliliters) of beer — about 5 percent alcohol
• 8 ounces (237 milliliters) of malt liquor — about 7 percent alcohol
• 5 ounces (148 milliliters) of wine — about 12 percent alcohol
• 1.5 ounces (44 milliliters) of 80-proof distilled spirits — about 40 percent alcohol

Be careful, though — some drinks may contain more alcohol than you realize. Often drinks are larger at bars and restaurants. And some drinks of the same size may contain more alcohol than others. For example, some light beers contain almost as much alcohol as regular beers, and some liquors contain a higher percentage of alcohol than others do.