The calories in alcoholic drinks, including wine, should be stated on bottles, campaigners said last night.

Brightly coloured nutritional information is increasingly visible on food products, but there is no legal requirement for manufacturers to show the number of calories in drink. Now the Food Standards Agency (FSA) is to consult on how the calorie content of alcoholic beverages should be communicated to drinkers.

Experts and opposition MSPs are calling for the information to be clearly visible on bottles, arguing that drink contributes to the obesity crisis and clear calorie information is more likely to put people off it than details of alcohol units. Low-calorie drinks, such as Bacardi Breezer Half Sugar, are already on the market.

Pilot research at Queen Margaret University College in Edinburgh found female students who went binge drinking were significantly fatter than those who did not.

However, there is concern that showing calories on labels may encourage slimmers to eat less to allow for calories in alcohol, against responsible drinking advice.

Professor Mike Lean, professor of human nutrition at Glasgow University, said calorie details should be clearly visible on beverages.

He said: "You do not have to be a very heavy drinker to discover a quarter of your calories are coming from alcohol.

"The rest of your diet is very critical if you have to get all the useful nutrients through only three-quarters of the calories you would normally eat."

He suggested the phrase "empty calories" could be used on labels to indicate booze with no nutritional benefit.

The Scottish Socialist Party is expected to include the move in its election manifesto. Carolyn Leckie, health spokeswoman for the SSP, said: "People are shocked when they find out how many calories they have consumed in a night out drinking."

She said that while people found units of alcohol confusing, they understood calories, so the information could curb drinking. Ms Leckie said: "Four alcopops in a night is the equivalent of four bags of fries. And alcohol has even less nutritional value than those."

However, Dr Jan Gill, researcher and senior lecturer in physiology and pharmacology at Queen Margaret University College, said possibly increasing the risk of eating disorders had to be considered in messages about the calorie content of alcoholic drinks.

"The suggestion that young women may save calories from food to allow' greater alcohol consumption is a real possibility," she said. "Nutritionally this would not make good sense. I think we need to give some thought to how best to display the calorific content of drinks, taking advice from nutritional or health experts."

The wine industry fears the impact of nutrition information on what is seen as a luxury market. Laurie Webster, former head of marketing at Oddbins and now managing director of wine label designer Raisin Sauvage, said that consumers should be given as much information as possible especially on health matters.

He added: "Wine isn't like a tin of beans or a loaf of bread. If moves are afoot to make wine labelling come more in line with food labelling, I just feel there is a potential for wine to become less special."

An FSA Scotland spokeswoman said its signposting campaign concentrated on foods which consumers found confusing from a nutritional point of view, such as ready meals and sandwiches.

She added: "There is no legal requirement for the calorie content of alcoholic drinks to be labelled unless a nutrition claim is made. The agency is about to publish a consultation on its draft strategy to address saturated fat and calorie intakes, and this will include consideration of calories from alcoholic drinks."

Food labelling is dealt with at a European level. The European Commission plans to update the legislation.