Red wine drinkers gained least weight
Women can enjoy a tipple and stay slim, according to a study that shows moderate drinkers gain less weight than teetotallers.
Women who drank red wine gained the least, but the results held for other wines, beers and spirits.
Although alcohol contains calories, the US researchers believe the women may have substituted it for other food.
Their work in the Archives of Internal Medicine followed over 19,000 women over 13 years.
The women recruited into the study were aged 39 or over and of normal weight at the time they joined.
Over the next 13 years, on average, they gained weight progressively.
Those who drank no alcohol gained the most weight, and there was an inverse relationship between weight gain and alcohol consumption.
Even after accounting for lifestyle, dietary factors and things like smoking and exercise, the study found those who drank the least gained the most weight.
Moderate drinking was classed as drinking up to about two 150ml glasses of wine a day.
Although the study did not include men, the authors believe the findings may not apply to men.
The women in the study who drank appeared to substitute alcohol for other food, meaning their overall calorie intake did not go up that much.
They say men who drink might not do this.
Also the way men and women break down alcohol in their liver may differ, which help might explain why women do not pile on the pounds.
But British researchers cautioned that people should be wary of concluding they can shed pounds by drinking more.
Catherine Collins, dietician and spokesperson for the British Dietetic Association, said: "It would be a mistake to think that drinking alcohol helps you lose weight."
She rejected the notion that the calories in alcohol don't contribute to weight gain.
"We know that alcohol calories do count. For binge drinkers, for example, alcohol can have a major impact on weight."
She pointed out that the study was based on women who were normal weight when they were recruited.
"These are quite an unusual group, who were likely to be mindful of keeping their body healthy," she said.
"Most women would have gained a few extra pounds by the age of 39.
"To be of normal weight by that age is quite a feat in itself.
"So findings about weight gain among this group may not be translate to others."
She said another limitation of the research was that it did not report how much snack food the participants ate.
"It may be that those who had wine as their treat ate less chocolate and snacks," she said.