Exercise recommendations on food and drink labels could help target the obesity crisis, according to new research.
There's little evidence that the nutritional information, like calorie count, on packaged food actually changes what foods we buy or eat.
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A recent study suggests a new approach: labelling food and drinks with symbols showing how much walking or running it would take to burn them off, writes the Guardian.
The label on a can of 138-calorie fizzy drink would display a symbol showing that it would take 26 minutes of walking or 13 minutes of running to burn off.
The team behind the research say this will help people avoid overeating and encourage them to get moving to burn off more energy.
Professor Amanda Daley of Loughborough University, the first author of the research, says it's clear this approach will be useful.
"We are not saying get rid of current labelling, we'd say add this to it."
She said a simple approach will work best, as we only tend to spend six seconds looking at food before deciding to buy it or not.
"In that [time] we've got to have something that you can easily understand and make sense of without having to have a PhD in mathematics to work out what [eating] a quarter of a pizza actually means."
"If I tell you something is going to take you 60 minutes of walking to burn, I think most people understand that and know that 60 minutes of walking is a long way."
In their research Daley and her colleagues analysed data from 14 previous studies looking at exercise-based labelling systems.
They found that compared with no labelling on food, people chose around 65 fewer calories per meal when exercise labels were on the food or menus.
"In restaurants and coffee shops, where we eat most of our high-calorie foods, you would typically see no labelling at all," said Daley.
But there was little difference compared with other labelling such as daily intake or calorie-only labeling.
Looking at the actual amount of calories consumed, the study found that people ate around 110 fewer calories when food displayed exercise labels compared with no labelling at all.
They might sound small, but Daley says the reductions add up across meals.
"People think that obesity is caused by gluttony. It isn't. Obesity is caused by all of us eating just a little bit too much," she said.
UK Royal Society for Public Health deputy chief executive Duncan Stephenson said in line with the research, the charity's own work showed that exercise labelling made people think before purchasing, and encouraged them to exercise.
The next step is to test it in real life in supermarkets and restaurants, he said.
The British Nutrition Foundation's Dr Stacey Lockyer said it's worth considering an approach that reduces people's daily calorie intake by up to 195 calories.
The average adult goes over the daily recommended calories by this amount, she said, while overweight or obese adults take in around 320 excess calories a day.
Dietitian Dr Frankie Phillips said exercise-based labelling could be confusing, and that focusing on calories doesn't necessarily tell us whether food is healthy.
"Calories labelled on a sandwich might come to around 400kcal whereas a chocolate confectionery bar might be 350kcal," she said.
"If calories are given central importance then the chocolate bar would appear to be a better choice, whereas a more balanced approach would obviously show that a sandwich is far superior nutritionally, despite being higher in calories."