Image copyright Hyrma/THINKSTOCK Image caption Pint of beer or packet of crisps? Both contain similar calories

MEPs have backed calls for calorie labels to be put on all alcoholic drinks in a vote at the European Parliament.

Food already has calorie information, but most alcohol is exempt.

Public health experts say mandatory labelling is needed to inform consumers and help halt rising rates of obesity.

However, the MEPs' vote is not binding and it will still take many months, or even years, before the proposals could become law.

Alcoholic drinks that contain more than 1.2% alcohol by volume are exempt from EU regulations on nutritional labelling that came in to force in 2011 covering all food and soft drink.

Many people don't realise that a large glass of wine contains the same number of calories as a slice of cake Glenis Willmott , MEP for the East of England

Glenis Willmott, MEP for the East Midlands, is a supporter of the call to implement mandatory alcohol labelling.

She said: "Europe is still the heaviest-drinking region in the world but many people don't realise that a large glass of wine contains the same number of calories as a slice of cake.

"In order to reduce the burden of alcohol-related harm, we must make sure people are given clear information to enable them to make informed choices."

And in the BMJ this week, Fiona Sim, chairwoman of the Royal Society for Public Health, says among adults who drink, an estimated 10% of their daily calorie intake comes from alcohol.

Yet a recent survey found that 80% of the 2,117 adults questioned did not know the calorie content of common drinks, and most were completely unaware that alcohol contributed to the total calories they consumed.

"Information provided to consumers must be honest and useful," she writes. "There is no reason why calories in alcohol should be treated any differently from those in food."

Some alcoholic-drink manufacturers have, voluntarily, begun to introduce nutritional labelling.

A spokesman for the Portman Group, which represents alcohol producers, said: "A number of drinks companies and retailers are already taking voluntary action when it comes to calorie labels.

"But we live in a digital age and should be thinking innovatively about how people access information, not just focusing on product labels which are limited in size and space.

How many calories

A large 250ml glass of 8% wine is 170 calories

The same amount of 14% wine is 230 calories

A 275ml alcopop can be 170 calories

A pint of 4% beer is more than 180 calories

Four pints on a night out equates of two-and-a-half burgers or 73 minutes of running

In comparison a sugary doughnut comes in around 200 calories

Source: Royal Society for Public Health, Drinkaware