Specials have hidden health cost

What's good for your wallet is often bad for your health, according to a study that found sugar-packed drinks are more likely to be discounted.

The Dietitians Association of Australia is calling for supermarkets to rethink what they put "on special", after a study revealed they were usually not the healthiest products in their aisles.

Researchers looked at about 1500 discounted drinks advertised for sale across four supermarkets, over a month, in New Zealand.

They found just 15 per cent were considered to be healthy - water, plain reduced- fat milk or plain reduced-fat soy drinks. The rest included softdrinks, sports beverages, flavoured waters and cordial.

Not only did unhealthy drinks dramatically outnumber healthy ones, they were also sold at larger discounts, according to the study published in the journal Nutrition & Dietetics.

"Our study shows healthy drinks are discounted less often than unhealthy drinks," said author Louise Signal, of the University of Otago.

DAA chief executive Claire Hewat said family eating and drinking habits were influenced by these discounting practices, and supermarkets should be promoting healthier foods.

- AAP