Women who drink a couple of glasses of red wine, beer or spirits a day are better at keeping the pounds off than teetotal women, according to a study published Monday.

Researchers at Brigham and Women's Hospital in Boston asked more than 19,000, normal-weight US women aged 39 or older how many alcoholic beverages they typically drank in a day, and then tracked the women for around 13 years.

The largest single group - 7,346 women or just over 38 percent - said they didn't drink a drop, the study published in the Archives of Internal Medicine, a publication of the American Medical Association, shows.

The second biggest group - 6,312 women or nearly a third of those surveyed - reported drinking the equivalent of around a third of a five-ounce glass of wine or a third of a 12-ounce beer. They did not explain how they managed to do so.

Twenty percent of the women said they drank the equivalent of up to a glass of wine, a 12-ounce beer, or a single-shot drink made with 80-proof spirits, while six percent said they had up to two drinks a day and three percent had more than two.

Over the 13-year follow-up period, the women who did not drink at all gained the most weight, and the women who had the equivalent of two drinks a day were the least likely to pack on pounds.

The best drink for keeping the pounds off was red wine, but all four types of tipple included in the study - red or white wine, beer and spirits - showed the same "inverse association between alcohol intake and risk of becoming overweight or obese," the study found.

The authors cautioned, however, against making recommendations on alcohol use as a tool against obesity, given the potential medical and psycho-social problems associated with drinking.

The women's alcohol intake was recorded in grams of alcohol.

A five-ounce (150 ml) glass of wine, 12-ounce beer or one mixed drink made with a single, 1.5-ounce shot of 80-proof alcohol all contain around 14 grams of pure alcohol and are considered "standard drink sizes" in the United States, according to the National Institutes of Health (NIH).