Think you’ve only had one or two glasses of wine? The truth may be that you’ve actually downed four or five.
The size of the glass, how you pour it, and the color of the wine can all change how much you drink — and think you’re drinking — according to new research at Iowa State and Cornell universities, published recently in Informa Healthcare’s journal, Substance Use and Misuse.
Participants in the study were asked to pour what they considered a normal drink in different types of glasses in various settings. It turned out participants poured 12 percent more wine into wide glasses than standard ones. They did the same when they poured wine while holding a glass, instead of setting it on a table.
“People have trouble assessing volumes,” Laura Smarandescu, an assistant professor of marketing at Iowa State, said in a release announcing the study’s results. “They tend to focus more on the vertical than the horizontal measures. That’s why people tend to drink less when they drink from a narrow glass, because they think they’re drinking more.”
The color of the wine also mattered. Participants poured 9 percent more white wine into a clear glass versus red, which contrasted more with the glass.
“If you ask someone how much they drink, and they report it in a number of servings, for a self-pour that’s just not telling the whole story. One person’s two is totally different than another person’s two,” said Doug Walker, an assistant professor of marketing at Iowa State and lead author of the study. “Participants in the study were asked to pour the same amount at each setting, but they just couldn’t tell the difference.”
The U.S. has focused heavily on food serving sizes. Most everyone knows, for instance, that the recommended portion of meat is the size of a deck of cards. Beer comes in standard bottles and shot glasses are standard sizes. Wine is different. And unlike eating too much, drinking too much can have immediate consequences.
It’s not reasonable to expect people to know exactly how much wine they’re pouring. But if they’re trying to keep track of how much they drink, or want to limit their intake, they’ll now know to watch out for wide glasses and drinks poured in hand.