Supermarket shoppers may soon be cruising the aisles with "intelligent" trolleys that warn them if they're buying too much junk food, technology experts say...

It will read each product's individual code to give customers information about calories, nutrition, ethical sourcing and the environment...

"Shoppers want barcode readers on their trolleys to calculate the nutritional content and tell them when they have blown their calorific budget," said EDS's Sion Roberts, director of consumer industries and retail.

"It's high-time that the humble barcode is recognized as a practical and cost-effective solution to consumers' thirst for information."

Some shoppers are already using advanced trolleys. Trials of touch-screen computers on shopping carts have been trialed in stores in the United States.