Fat tally at supermarket checkout

They say you are what you eat, but at least only you know how much you ate this Christmas. However, a team of scientists now say that the secret’s out. Just by looking at your supermarket till receipts, they can estimate your consumption of fat and energy intake.

“Over 90% of our food is bought from supermarkets,” says Joan Ransley, Director of the Public Health Nutrition Unit at Leeds University. “We thought that till receipts would tell us lots of information about the nutrition of households.”

The research team studied the four weeks’ worth of receipts from 284 shoppers who said they spent at least 60% of their food bill at Tesco and at other supermarkets. Each member of the household also kept a four-day food diary. All the food eaten at home was weighed and meals eaten elsewhere were recorded and used in the analysis.

The analysis showed that the on average around 36% of a household’s energy intake comes from fat – 3% above the recommended levels set by the Department of Health.

“This pilot study shows a strong relationship between the amount of energy and fat purchased from supermarkets and the amount consumed,” says Dr Ransley. “Assessment of individual food consumption is prone to under reporting and inaccuracies. Therefore, the use of till receipts could be a novel, inexpensive and effective way of evaluating household food consumption.”

Wider studies could assess the nutritional intake of individuals and specific groups in society and examine diet-disease relationships between different geographical regions and countries.

“Supermarkets could play a role in helping us reduce the amount of fat in our diets,” suggests Dr Ransley. “Advances in scanning technology could lead to the development of a ‘fat tally’ of the foods in our trolleys and this could be shown on a graph on the receipt, plotted against the UK recommended levels of energy from fat.” It might be just enough to encourage you to put the triple choc, sticky toffee doughnuts back on the shelf.