Alcoholic drinks have calories, say experts, so labels should say how many we're drinking.

Labels revealing how costly a glass of wine or beer could be in terms of weight gain could soon be on the way, as the Government explores making them mandatory.

Alcohol manufacturers already label drinks with standard drink measurements and some voluntary health warnings.

Now, the Government is considering adding another requirement - labelling the number of kilojoules each drink contains.

"They [alcoholic drinks] contribute quite a large proportion of our energy, around about 5 per cent, which is around about the same as sugar," said Auckland University of Technology nutrition professor Elaine Rush.


"If we are going to have sugar labelling mandatory on products, we should not be ignoring the elephant in the room of alcohol."

Food Standards Australia and New Zealand is considering whether people should be told the energy content of drinks, in the same way they are told the kilojoules in other products.

Two years ago, an independent panel charged with reviewing food labelling recommended kilojoule labelling for all alcohol products and a nutrition information panel for pre-mixed alcoholic drinks.

Food Standards has commissioned a cost-benefit analysis on the concept, including looking at how energy labels might change buying and consumption.

Lion's external relations director, Liz Read, said the brewer was in regular consultation with the Ministry of Primary Industries on the review.

Asked if Lion was opposed to kilojoule labelling, Ms Read said the process had to be worked through.

"Lion is pretty focused on promoting moderation and the idea of alcohol being a legitimate part of a healthy, balanced lifestyle."

There was also little evidence that consumers made decisions based solely on energy information displayed on food.


But Professor Rush said alcohol was an energy-dense product, which meant it contributed to weight gain.

She said a common response to calls for more labelling on such products was that individuals were free to choose what they ate or drank.

"To have a choice, you need to be properly informed. Alcoholic drinks are energy dense, and nutrient poor.

"We have a big problem in New Zealand, we are growing too quickly in size. Sugar is receiving a lot of attention, and I think we need to make sure the public are as well informed about alcohol and the products they buy off the shelves."