That news comes from a study published in the Journal of the American Medical Association.
"What we found was more gastric bypass patients reported symptoms of alcohol use disorder in the second year after surgery, compared to pre-surgery or the first year after surgery," researcher Wendy C. King, PhD, assistant professor of epidemiology at the University of Pittsburgh Graduate School of Public Health, tells WebMD.
The study will also be presented today in San Diego at the American Society for Metabolic and Bariatric Surgery's annual meeting.
Alcohol Abuse After Weight Loss Surgery
For years, there have been anecdotal reports of alcohol abuse becoming more likely after weight loss surgery. But studies on that haven't been conclusive, King tells WebMD.
King's new study included nearly 2,000 obese U.S. men and women who had weight loss surgery at any of 10 U.S. hospitals.
They filled out surveys before surgery, a year later, and the year after that.
The survey included questions about alcohol use. The researchers used it to identify who had alcohol use disorders, defined as abuse or dependence.
There was no spike in alcohol use disorders in the first year after weight loss surgery. While 7.6% of patients had alcohol problems before surgery, 7.3% had them one year after.
But in the second year, 9.6% had an alcohol problem.
More than half of those who had alcohol issues after surgery did not have them before, King says.
Weight Loss Surgery and Alcohol Problems: A Closer Look
When King looked more closely, she found that the Roux-en-Y procedure more than doubled the association to alcohol problems. But that's not proof that the surgery (or any other type of weight loss surgery) caused anyone to abuse alcohol. An association, like the one in this study, doesn't prove cause and effect. Most of the people in King's study -- 1,339 -- had Roux-en-Y.
Other people in the study had different weight loss procedures, such as the laparoscopic gastric band.
King says after the Roux-en-Y procedure, they believe alcohol is metabolized differently.
"The alcohol gets to the small intestine more quickly," she says.
Some patients say they feel the effects of alcohol more quickly than they did before the surgery, she says.
However, King's team did not assign people to any particular type of weight loss surgery. So the researchers weren't directly testing whether some surgeries were more of a risk than others.
Alcohol use disorders were also more likely to develop in men, younger people, recreational drug users, smokers, people who felt socially isolated, and people who drank two or more drinks per week.
Bariatric Surgery and Alcohol Abuse: Perspective
The new research is not surprising, says Robin Blackstone, MD, president of the American Society for Metabolic & Bariatric Surgery.
She reviewed the study for WebMD but was not involved in it.
As a result of the bypass procedure, the alcohol doesn't get metabolized normally, says Blackstone.
"I tell people they should absolutely not drink alcohol at all if they have the gastric bypass," Blackstone tells WebMD.
She says her advice applies only to the Roux-en-Y procedure. The American Society for Metabolic & Bariatric Surgery does not have a policy on alcohol use after Roux-en-Y, she says.
If patients are treated at a nationally recognized center, she says, they will have an evaluation to uncover alcohol problems and other issues.
The new research is valuable, Blackstone says. "It not only confirms the fact that there are some people affected by this alcohol sensitivity, but it also tells us who those people are who are most at risk."
With that information, doctors can suggest the best weight loss surgery for specific patients, Blackstone says.
King has no disclosures. Co-author Anita Courcoulas, MD, MPH, of the University of Pittsburgh, reports receiving research grants from Allergen, Pfizer, Covidien, and EndoGastric Solutions. She is a consultant for, and serves on the scientific advisory board of, Johnson & Johnson's Ethicon Healthcare System.
Another co-author, Walter J. Pories, MD, of East Carolina University, is a consultant to Johnson & Johnson Ethicon Endo-Surgery Inc. and receives grants from them and GlaxoSmithKline.
Ethicon Endo-Surgery is the maker of Realize, an adjustable gastric band.
The study was funded by the National Institutes of Health and various universities and medical centers.