Junk food snacks should be labelled with how long you need to exercise to burn it off, a review has found.
Scientists calculated that displaying how many minutes or miles of physical activity were needed would cut 200 calories from daily diets on average.
The NHS currently recommends around 2,500kcal for men and 2,000kcal for women daily but many consume much more than this.
The physical activity calorie equivalent (PACE) food labelling shows eating 229 calories in a small bar of milk chocolate would require about 42 minutes of walking or 22 minutes of running to burn off.
Experts say such shock labelling is needed to stop us filling our faces at mealtimes.
A team led by Loughborough University reviewed 15 studies to compare the impact of PACE labelling and the current labelling.
They found listing how much exercise was needed to burn off food and drink cut 65 calories per meal on average.
The label on a sugary fizzy drink containing 138 calories would carry a logo saying this equates to 26 minutes of walking or a 13-minute run.
A shop bought chicken and bacon sandwich with 445 calories would show 1 hour 22 minutes for walking and 42 minutes for running.
A packet of crisps equates to 31 minutes of walking or 16 minutes of running. And a blueberry muffin comes in at 48 minutes of walking and 25 minutes of running.
The technique could be a useful tool to help people decide whether the calories are “worth it,” said sports scientist Professor Amanda Daley.
“Unlike other types of food labelling, PACE labelling has the potential to serve as a continual reminder to the public about the importance of participating in regular physical activity,” she said.
“It is an example of an environmental intervention that seeks to nudge the public towards making healthy food choice and to demonstrate restraint in their eating.”
Three years ago the Royal Society for Public Health called for PACE labelling to replace the current system.
The latest findings published in the Journal of Epidemiology and Community Health provide the first strong evidence that backs the suggestion.
More than two-thirds of the UK population is either overweight or obese - raising the risk of heart disease, cancer, diabetes and other life-threatening illnesses.
Senior author Prof Daley added: “One way of calorie consumption is nutritional labelling but current evidence shows current front-of-pack nutrition information on food and drinks is having a limited effect on changing purchasing or eating behaviours.
“Many people do not understand the meaning of calories or grams of fat in terms of energy balance.
“A key challenge to limiting energy consumption is the significant under-estimation by the public of the amount of calories and fat in food and drinks.”
