Over 90% of our food is bought from supermarkets so till receipts can tell us lots of information about the levels of fat and energy households may be consuming

Joan Ransley, Leeds University

In the future, looking at till receipts could allow detailed analysis of people's nutritional intake, including research into links between diet and disease.

Scanning techniques could also lead to the development of a "fat tally" of foods in a shopper's trolley, which could eventually be shown as a graph on the receipt - with the recommended levels also shown.

Joan Ransley, director of the PHNU, said: "Over 90% of our food is bought from supermarkets so till receipts can tell us lots of information about the levels of fat and energy households may be consuming.

"Our research indicates that supermarkets could play a role in helping us reduce the amount of fat in our diets."

Checks

The researchers looked at 28 days-worth of till receipts from 284 people in Leeds who said they spent at least 60% of their food bill in supermarkets.

Each person in a household also kept a four-day food diary.

All food eaten in the house was weighed, and meals eaten elsewhere were recorded and included in the analysis.

People often under-report what they eat in food-consumption studies, and the Medical Research Council, which backed the research, said till receipts could be a "novel, inexpensive and effective" way of checking household fat consumption.

'Apple-shape' explanation'

Scientists say their discovery of an enzyme linked to "apple-shaped" or visceral obesity, could one day lead to drugs to help people prone to put weight on on their belly.

Apple-shaped people are prone to problems such as diabetes and high-blood pressure.

Researchers from the UK and US tested genetically engineered mice and found that visceral obesity was the result of too much of enzyme called 11beta HSD-1.

They believe the enzyme could amplify the production of a key hormone which influences metabolism.

The mice put on extra fat around their middle, and developed many of the metabolic disorders linked to 'apple-shaped' obesity.

The study was published in the journal Science.