Weight Loss Surgery Can Raise Risk of Alcohol Problems, Study Finds

A new study says that people who have weight loss surgery need to be very careful about drinking alcohol afterward. Researchers found that after this type of surgery, the body absorbs alcohol much faster than before. This means a person can get drunk more quickly — and stay drunk longer — even if they drink the same amount as before the operation. The study was published in the International Journal of Obesity.

Weight loss surgery, also called bariatric surgery, shrinks the size of the stomach. This helps people eat less and feel full faster, which leads to weight loss. But changing the stomach also changes how alcohol moves through the body. Normally, an enzyme in the stomach lining breaks down some alcohol before it enters the bloodstream. After surgery, that protective step is mostly gone, so more alcohol gets into the blood — and it gets there faster.

Researchers at the Norwegian University of Science and Technology tested 33 people before and after they had bariatric surgery. During the tests, each person drank a carefully measured mix of vodka and orange juice. Scientists then checked their blood alcohol levels at different times. The tests happened before surgery and again at three months, one year, and three years after the procedure.

The results were striking. Alcohol levels in the blood nearly doubled after surgery compared to before. People also reached their highest blood alcohol level in about half the time. Lead researcher Magnus Strømmen said these effects are likely to last for the rest of a patient's life, which makes the finding especially important.

The study also looked at a much larger group — about 17,800 patients in Norway who had bariatric surgery between 2008 and 2018. Among those patients, people who had a gastric bypass had a 69% higher chance of developing alcohol problems compared to those who had a gastric sleeve procedure. Both types of surgery carry risks, but the bypass showed a stronger effect. Strømmen was clear that the sleeve surgery is not without risk either.

Strømmen said patients need to be warned that their relationship with alcohol will change after surgery. Friends and family may expect them to drink the same as before, but their bodies now work differently. He said patients must learn to say no and understand why. This kind of education, he believes, can help prevent serious drinking problems from developing.

Doctors also need to do a better job of asking patients about their drinking habits before surgery, Strømmen said. A detailed conversation about alcohol history and risk factors should happen before any operation is approved. He also asked patients to be honest with their doctors about their habits. Being open and informed, he said, gives patients the best chance at a healthy life after surgery.