Food packs should display how much exercise a person would need to take to burn off the calories contained in the product, UK researchers say.
Appreciating it would take four hours to walk off the calories in a pizza or 22 minutes to run off a chocolate bar creates an awareness of the energy cost of food, they say.
The labels would help people indulge less, exploratory studies suggest.
The aim is to encourage healthier eating habits to fight obesity.
According to the researchers from Loughborough University, who looked at 14 studies, this type of labelling could cut about 200 calories from a person's daily average intake.
This may not sound like much but, they say in the Journal of Epidemiology and Community Health, it would have an impact on obesity levels across the country.
More than two-thirds of adults in the UK are overweight or obese.
Lead researcher Prof Amanda Daley said: "We are interested in different ways of getting the public to make good decisions about what they eat and also trying to get the public more physically active."
And labelling food with "exercise calories" made it easier for people to understand what they were eating and nudge them into making better choices.
- The amount of energy in an item of food or drink is measured in calories (kcal)
- Our bodies need them to function
- But eating too many without burning them off causes obesity
- Eating a little bit too much every day adds up and the excess is stored by the body as fat
- Men need about 2,500 kcal a day and women about 2,000 kcal
Prof Daley said many people would be shocked to realise how much physical exercise would be required to burn off calories from certain snacks and treats.
"We know that the public routinely underestimate the number of calories that are in foods," she said.
"So if you buy a chocolate muffin and it contains 500 calories, for example, then that's about 50 minutes of running.
"This definitely isn't about dieting.
"It's about educating the public that when you consume foods, there is an energy cost, so that Read More – Source