Food labelling needs to change so people can see how much exercise they would need to do to burn off the calories, the Royal Society for Public Health (RSPH) has said.
The RSPH said "activity equivalent" calorie labelling should be put on the front of food and drink packs, with pictures showing the exercise needed to match the calorie intake.
It comes as a poll of more than 2,000 people for the RSPH found 63% would back the change to food labels. Some 53% thought it would make them do more exercise, eat less or choose healthier products.
People were three times more likely to say they would take some form of exercise after viewing "activity equivalent" calorie labels than after viewing current "traffic light" labels alone, research also found.
The new call is included in a policy paper by RSPH which shows many people find current front-of-pack nutritional information confusing, with many suffering "information overload".
Shirley Cramer, chief executive of the RSPH, said: "Although nutritional information provided on food and drink packaging has improved, it is evident that it isn't working as well as it could to support the public in making healthy choices.
"Activity equivalent calorie labelling provides a simple means of making the calories contained within food and drink more relatable to people's everyday lives, while also gently reminding consumers of the need to maintain active lifestyles and a healthy weight."
A spokesman for the Food and Drink Federation said: "Weight gain occurs when more calories are consumed than are burned during physical activity.
"For this reason, initiatives which reinforce the well-understood calorie message and encourage people to be more active are to be encouraged.
"As an industry, we are looking at what more we can do to help people use the existing nutritional information provided to understand how different foods and drinks fit within a healthy lifestyle.
"Activity equivalent information is an interesting concept and the role it could play in driving meaningful behaviour change is certainly worth exploring."