Alcohol belly? Gut health expert reveals EXACTLY why booze makes you poop differently

It is known that drinking too much can lead to headaches, fatigue and stomach upset, but why does drinking one too many send you running to the toilet the next day?

Now an expert has revealed how alcohol is wreaking havoc on your body and your digestive system.

Vincent Ho, associate professor of gastroenterology at Western Sydney University, said alcohol messes up the way your body processes food, especially how long it takes for food to travel through the intestines.

Alcohol can speed the movement of food through the stomach and intestines, causing diarrhea. It also reduces nutrient absorption and people who indulge in sugary alcoholic drinks are more likely to experience bathroom discomfort the next day.

The graph above shows how long it takes for the body to return to baseline after a weekend of drinking

However, not all alcohol is the same and some can even have the opposite effect.

Drinks such as beer and wine speed up food transit, but vodka and whiskey slow it down, causing a feeling of fullness or discomfort.

A study in rats found that those exposed to high doses of alcohol experienced delays in food processing in the small intestine. This could indicate that people who engage in binge drinking – as opposed to repetitive heavy drinking – may experience more constipation than diarrhea.

In a 2022 study, 500 people recorded their bowel movements and had their stool collected for analysis. Based on self-report surveys, researchers found that people who reported an episode of heavy drinking had harder and firmer bowel movements.

Researchers believed that the short period of heavy drinking led to a delay in food processing in the intestines. And the longer food remains in the intestines, the more water from feces is reabsorbed into the body, leading to dry and hard poop.

However, not everyone has experienced this. In people with pre-existing digestive problems, such as irritable bowel syndrome, binge drinking led to diarrhea, nausea and abdominal pain.

And chronic alcohol use can even have long-term effects on your gut, as it has been linked to lactose intolerance, small intestinal bacterial overgrowth and reduced nutrient absorption.

If you regularly suffer from digestive problems, here's what you can do, Mr. Ho saidis to limit alcohol intake and pay attention to which type of alcohol affects you most.

If you experience diarrhea after a night out, it may be helpful to avoid mixing alcohol with caffeinated drinks, which are known to cause intestinal problems.

If constipation is the problem, staying hydrated is important. Mr Ho recommends drinking water even before drinking alcohol.

Drinking water between alcoholic drinks and before going to bed can also help prevent discomfort.

Eating protein- and fiber-rich foods can be helpful. Having food in your stomach before drinking can help soften the effects of alcohol on the intestinal lining.

Mr Ho said changes in bowel movements after drinking alcohol are usually short-lived and harmless and resolve themselves within a few days.

However, if symptoms persist for more than a few days after drinking, it could be a sign of a digestive problem.