Published: 28 February 2020
The size of glass used to serve wine in restaurants can influence the amount of wine people drink, suggests new research funded by NIHR and carried out at the University of Cambridge.
Previous research carried out by the group at the Behaviour and Health Research Unit suggested that serving wine in larger glasses - while keeping the measure the same - led to a significant increase in the amount of wine sold.
The new results, published in the journal Addiction, found that more wine was sold when restaurants served it in larger 370ml sized glasses rather than 300ml sized glasses. Less wine was sold when they used smaller 250ml sized glasses.
The restaurants studied were serving wine either by the bottle or in standard measures of 125, 175 or 250ml. The effect was not seen in bars.
The research team were looking at results from all of their previous studies and analysing them as a whole. The studies focused on bars and restaurants in Cambridge where the researchers were able to control the sizes of glasses used, and the team used 300ml glasses as the reference point to compare differences in how much wine was drunk.
In restaurants, when glass size was increased to 370ml, wine sales increased by 7.3%. Reducing the glass size to 250ml led to a drop of 9.6%, although this result was less certain. Curiously, increasing the glass size further to 450ml made no difference compared to using 300ml glasses.
The researchers believe that larger glasses can increase consumption because drinkers tend to measure their wine drinking in terms of glasses - ‘I’ll have one glass’. Larger glasses containing the same measure of wine look less full, possibly encouraging further drinking. And when drinkers are pouring their own wine from a bottle, they may be likely to fill larger glasses with more wine while still counting it as one glass.
The researchers’ previous work shows that wine glasses have increased in size almost seven-fold over the last 300 years - a wine glass 300 years ago would only have held about a half of today’s small measure. Glasses have doubled in size since 1990, and during this time the amount of wine consumed in England has quadrupled, even though the number of wine drinkers has stayed the same.
Senior author Professor Dame Theresa Marteau said, “If we are serious about tackling the negative effects of drinking alcohol, then we will need to understand the factors that influence how much we consume. Given our findings, regulating wine glass size is one option that might be considered for inclusion in local licensing regulations for reducing drinking outside the home.”
Professor Ashley Adamson, Director of the NIHR School of Public Health Research, said: “We all like to think we're immune to subtle influences on our behaviour – like the size of a wine glass – but research like this clearly shows we're not.
"This important work helps us understand how the small, everyday details of our lives affect our behaviours and so our health. Evidence like this can shape policies that would make it easier for everyone to be a bit healthier without even having to think about it.”