March 9, 2010 -- Cheers, ladies! Researchers now say light to moderate drinking may keep women from gaining too much weight.
Normal-weight women who drank 5 to 30 grams of alcohol daily gained less weight and had a lower risk of becoming overweight or obese than either teetotalers or those who drank too much, according to a report in the March 8 Archives of Internal Medicine.
How much is that? A 12-ounce light beer contains about 11 grams of alcohol, while 5 ounces of red wine contains 15 to 16 grams and a 1.5 ounce shot of 80-proof whiskey contains about 14 grams of alcohol.
Despite their findings, Dr. Lu Wang of Brigham and Women's Hospital in Boston and colleagues cautioned against recommendations for drinking alcohol as a weight control measure.
"Taking into account the potential medical and psychosocial problems related to drinking alcohol," they wrote, "any recommendation on alcohol use should be made for the individual after carefully evaluating both adverse and beneficial effects of the drinking behavior in broad context."
Alcohol has a relatively high caloric value and may, in the long run, result in weight gain, some researchers have said. But epidemiological studies haven't provided consistent evidence of that relationship.
So the researchers conducted an analysis of data from the prospective cohort Women's Health Study of 19,220 women over age 38 who were disease-free and had a normal body mass index (BMI) at the outset.
They reported their weight and alcohol consumption on a questionnaire at that time, and reported their weight again on eight annual follow-up questionnaires.
The women were followed for an average of 12.9 years. During that time, 41.3 percent of the women became overweight or obese, while 3.8 percent became obese.
Average weight gain was 3.63 kg -- about 8 pounds -- for those who didn't drink, compared with 1.55 kg -- about 3.5 pounds -- for moderate drinkers.
The researchers found an inverse relationship between alcohol consumption and subsequent weight gain. "Weight gain was largest for women who did not consume alcohol and then monotonously decreased with increasing total alcohol intake," they wrote.
After taking into account many other variables, including nonalcohol caloric intake, physical activity, and other lifestyle factors, the relationship strengthened, with the risk of becoming overweight or obese diminishing as women drank more moderately.
But the risk of weight gain did not decline further once women drank 40 grams of alcohol per day or more.
This is not great news for men, however, the researchers say. That's because mean and women drink differently: men add alcohol to their daily dietary intake, while female drinkers substitute alcohol for other foods without increasing total calories.
In this study, for instance, women who drank alcohol had lower caloric intake from nonalcohol sources, particularly carbohydrates.
The investigators said there may be gender differences regarding the metabolism of alcohol.
But they cautioned that "complex interrelationships" exist between drinking habits and various lifestyle, clinical, and physiological factors, which may help explain inconsistent findings in studies past.