Women who drink moderate amounts of alcohol don't gain as much weight in midlife as those who abstain, a study has found. However, drinking should not be heralded as a new diet, said the authors and alcohol abuse experts.
The study, published Tuesday in the Archives of Internal Medicine, is the first to find that alcohol may curb weight gain in women.
Typically, alcohol consumption is not advised for people trying to lose or avoid gaining weight. A 5-ounce glass of wine contains about 125 calories, and a regular 12-ounce beer has about 150.
Researchers at Brigham and Women's Hospital in Boston examined data from 19,220 women enrolled in the long-running Women's Health Study. The women, all originally of healthy weight, provided health and lifestyle information over an average of 13 years.
After doing their best to adjust for other factors that influence weight, the researchers found that compared with women who did not drink, women who drank 15 to 30 grams a day -- the equivalent of a drink or two -- were 30% less likely to be overweight or obese at the end of the study period.
There were too few heavier drinkers to evaluate the effect on body weight of greater quantities of alcohol.
The effects were found for beer, red wine, white wine and spirits, although the strongest association was found with red wine.
It's unclear what accounts for the association, the authors said. Women burn more calories after drinking than men do, however, providing a possible biological explanation.
But some of the link might not be due only to alcohol consumption but to other things drinking women tend to do. Women who drank more alcohol in the study consumed fewer calories from other foods. They were more likely to smoke, were more physically active, had lower body mass indexes at the start of the study and had less healthful diets.
The research should not translate into advice for women, said Dr. James C. Garbutt, a professor of psychiatry at the University of North Carolina's Bowles Center for Alcohol Studies.
"If the message is that by drinking some alcohol you're going to lose weight, that's a potentially complicated and dangerous message," he said.