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Beware of Alcohol after Gastric Bypass

Mar 23, 2011

One glass of wine will raise alcohol levels significantly more after gastric bypass surgery, and affect the patients driving skills.

Researchers say that gastric bypass patients need to be extra careful about drinking after they’ve had surgery. It’s a precaution that should be passed along to virtually all the people who have gastric bypass.


The researchers compared the effects of a glass of wine, consumed in one minute, in 19 patients before gastric bypass surgery and three and six months later. The study did not look at other forms of weight loss surgery.

Using a breathalyzer test, the authors found that on average, the peak breath alcohol level after a glass of wine was 0.024% before surgery. Six months later, it was 0.088%, which is higher than the legal driving limit of 0.08%.

“One glass of wine made people legally intoxicated,” said Dr. John Morton, the director of bariatric surgery at Stanford University and the lead researcher on the study.

It also took 88 minutes for people’s alcohol levels to return to zero after the surgery, compared to 49 minutes before the surgery.

Dr. Morton stated that, the changes are likely due to the stomach no longer being available to help process the alcohol. Weight loss itself did not account for the changes in breath alcohol or tipsiness, according to the researchers.

After the surgery, all of the patients in the study reported that they felt some effects of the wine, such as dizziness, warmth, or double vision. Before the surgery, eight out of 10 patients felt some effects.

“I think these issues with alcohol after surgery are still relatively rare,” because people who have weight loss surgery make an effort to avoid the empty calories in alcohol, Dr. Morton said.

J Am Coll Surg 2011;212:209-214.