Ahmed Arif, from Texas Tech University Health Sciences Center, in Lubbock, USA and James Rohrer, from Mayo Clinic, Rochester, USA, analysed the results of the National Health and Nutrition Examination Survey III in a subset of 8,236 non-smoker respondents. The respondents had all filled a questionnaire about their drinking habits and their body mass index (BMI) had been measured.

Out of the sample studied, 46% were 'current drinkers' and drank at least one drink a month on average. Individuals who drank four or more drinks per day were classified as heavy drinkers. Obesity was defined as a BMI equal to or higher than 30.

The results of the study show that current drinkers had 0.73 lower chances of being obese than non-drinkers. Current drinkers who drank one to two glasses regularly, but less than five drinks per week, were significantly less likely to be obese than non-drinkers and heavy drinkers. Heavy drinkers were 46% more likely to be obese than non-drinkers.

The mechanisms of the protective effect of alcohol on obesity are not well understood and the authors emphasize that "the data give no evidence to advise non-drinkers to start drinking alcohol just for reducing body weight."

They add: "However, the evidence reported here argues against a strategy of promoting complete abstention at least among those who regularly consume alcohol."