The size of your wine glass influences how much you drink, University of Cambridge study finds

Diners drink more wine if they have bigger glasses, a study suggests.

University of Cambridge researchers found that restaurants using 370ml glasses - rather than 300ml - sell 7.3 per cent more wine.

And they sell 9.6 per cent less when they used 250ml glasses, compared to 300ml glasses.

The effects were not seen in bars, indicating that glass size is a factor when diners tend to pour their own drinks.

Dr Mark Pilling, first author of the study, said: “Pouring wine from a bottle or a carafe, as happens for most wine sold in restaurants, allows people to pour more than a standard serving size, and this effect may increase with the size of the glass and the bottle.

“If these larger portions are still perceived to be ‘a glass’, then we would expect people to buy and consume more wine with larger glasses.

“As glass sizes of 300ml and 370ml are commonly used in restaurants and bars, drinkers may not have noticed the difference and still assumed they were pouring a standard serving. When smaller glass sizes of 250ml are available, they may also appear similar to 300ml glasses but result in a smaller amount of wine being poured.”

Intriguingly, increasing the glass size to 450ml made no difference compared to using 300ml glasses.

“Very large glasses, such as the 450ml glasses, are more obviously larger, so drinkers may have taken conscious measures to reduce how much they drink, such as drinking more slowly or pouring with greater caution,” suggested Dr Pilling.

The work by the university’s Behaviour and Health Research Unit was a ‘mega-analysis’, bringing together all of its previously published datasets from studies carried out between 2015 and 2018 at bars and restaurants in Cambridge.

Professor Dame Theresa Marteau, senior author, 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.”

The work was funded by the National Institute of Health Research (NIHR)

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.”

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