Patients who undergo gastric bypass surgery must consume only small amounts of food, but a new study has found that the same concept also applies to alcohol. 

The report published in the latest issue of JAMA Surgery shows that people who have gastric bypass are less able to handle their liquor. Led by Dr. Samuel Klein, director of the Center for Human Nutrition at Washington University's School of Medicine in St. Louis, the research team analyzed 17 obese women. Eight had undergone gastric bypass surgery one to five years before the study began, while the other nine had yet to have the operation.

All of the women consumed either two alcoholic drinks or two non-alcoholic “dummy” drinks in a 10-minute period. The researchers found that blood alcohol levels in the bypass group rose far more quickly than those in the non-bypass group and ultimately reached levels that were twice as high. All it took was two drinks to get bypass patients into the equivalent of a binge-drinking episode. The BAC levels in the bypass group also exceeded legal driving limits, unlike the non-bypass group.

"This surgery literally doubles the amount of alcohol that immediately enters your bloodstream," said Klein. “It also increases the patient's long-term risk for alcoholism, because the risk for a binge episode of drinking goes up. And we know that binge drinking increases the risk for going on to develop alcoholism in the future.”

However, doctors who perform gastric bypass surgery said the findings are common knowledge among other bariatric professionals.

"It's about physiology ... we have alcohol receptors in the stomach and the liver. And if you bypass and remove a portion of either of these, you have a change in blood alcohol levels,” said Dr. John Morton, chief of bariatric and minimally invasive surgery at the Stanford University School of Medicine. “[But] this is a phenomenon we only see with this specific type of bariatric surgery. You don't see it with gastric band or other weight-loss surgeries.”