It's not pee you're worried about the next morning. According to gastroenterologist Dr. Kathlynn Caguiat, "Alcohol can increase gut motility and it doesn't get broken down before it reaches the colon, where bacteria feast on these, resulting in bloating and diarrhea." Those bacteria love the alcohol you feed them, and they repay you with extra gas and crap.
What's more, increased gut motility means everything's moving more rapidly than usual. That in turn means the colon has less time to absorb any water, which can result in watery stool and diarrhea.
And the worst offenders are…
"The more concentrated the alcohol, the worse the reaction will be," Shah warns, which explains the severe reactions whiskey can provoke the next morning. Liquors will produce the worst booze craps, in other words.
But beer won't exactly be your friend either. This is because the body produces enzymes to assist in breaking down the complex carbohydrates found in your favorite suds as they travel to the small intestine. When you're slinging high-carb options like beer down your gullet fairly quickly -- and ethanol is speeding up the digestive process, remember -- some of the carbs will make it to your large intestine without breaking down. The bacteria in the large intestine start fermenting those carbs, resulting in gas, cramping, loose stool, and diarrhea.