'Rule of thumb' can prevent over-drinking

Next time you open a bottle of wine, serve yourself half a glass and you are less likely to drink too much!
Sticking to a general rule of pouring just half a glass of wine significantly limits the likelihood of overconsumption, even for men with a higher body mass index, a new study suggests.
Laura Smarandescu, lead author and an assistant professor of marketing at Iowa State University, says the research team looked at a variety of factors to understand and control over pouring. They found BMI affected how much men poured, but had no influence on women.
However, people who used a "rule of thumb," such as a half-glass rule or a two-fingers-from-the-top rule when pouring wine, poured less regardless of BMI or gender.

"About 70 per cent of the people in the sample used the half-glass rule, and they poured significantly less by about 20 per cent," Smarandescu said.
"It's a big difference. We would suggest using a rule of thumb with pouring because it makes a big difference in how much people pour and prevents them from over-drinking," said Smarandescu.

Men with a higher BMI, who did not use a rule of thumb, poured more - 31 per cent more for men considered overweight or obese and 26 per cent more for men at the midpoint of the normal BMI range.
While BMI did not affect how much women poured, those at the midpoint of the normal BMI poured 27 per cent less when using the half-glass rule than those who did not.

Researchers were not surprised to find men poured more than women, which is consistent with other studies of alcohol consumption. However, they did not expect the half glass rule would be an exception to men pouring more.
"In this study, we had every expectation that men would always pour more than women, no matter what. But what we found is that the rule of thumb effect is so strong that men using a rule of thumb at all levels of BMI actually poured less than women who were not using a rule of thumb," said Doug Walker, an assistant professor of marketing at Iowa State.

Researchers asked 74 college students and staff to pour wine in a variety of settings so that they could control for the size, shape and colour of the glass, as well as if wine is poured with a meal.
They poured both red and white wine from bottles with different levels of fullness. Participants were told to pour as much as wine as they normally would in one setting.
Drinking is more socially acceptable for men than women, which is one explanation for why BMI did not have the same effect on women, researchers said.
"It is essential for all drinkers, especially men of higher BMIs, to have a rule of thumb for self-serving, because eye-balling a serving size is a difficult task and will often lead people to pour too much," said Brian Wansink, a professor at the Cornell University Food and Brand Lab.

The study appears in the International Journal of Drug Policy.