According to the researchers, consumers spend an average of six seconds looking at a food product before making a purchase decision creating a clear need for easy-to-interpret, meaningful information.
But previous research suggests that current front-of-pack information, such as the UK's voluntary traffic light logo, may be too detailed and therefore confusing. This means the the information is often ignored, particularly in low socioeconomic status groups and in those with poor nutrition knowledge.
Exercise labels are one way of applying nutrition information to real-life situations, according to University of Liverpool researchers.
A promising avenue
They showed 458 participants images of five different food types (breakfast bar, café muffin, biscuits, chocolate bar and crisps) and five different beverage types (cola, sports drink, milkshake, café coffee and fruit juice). For each food or beverage type, individuals were shown a higher and lower calorie version, with options matched for type and brand to ensure brand preference did not influence choice.
Subjects were shown either the calorie content or the calorie content and amount of walk that would be required to burn off the calories, and then selected which of the products they would buy.
The physical activity label group resulted in "significantly lower" energy snack and beverage choices than the calorie label group, say the researchers.
Moreover, the exercise labels were the most effective for all participants, regardless of individual factors such as sex, weight (as measured by Body Mass Index, or BMI), diet status, calorie literacy, numerical literacy and general physical activity levels.
“To our knowledge, this is the first study to show such effects for physical activity labels and provides tentative evidence of a promising avenue for public health research and policy in this area,” the authors write.
“Physical activity labelling should be considered as a public health policy initiative that, in the context of an obesity epidemic, could make it simpler for consumers to make lower energy, informed food choices.”
Despite some limitations, such as the hypothetical nature of the food choices being made which may not translate to real-life situations, the effects of the exercise labels were “robust”.
FDF: 'It's certainly worth exploring'
A spokesperson for the UK's industry association Food and Drink Federation told FoodNavigator:“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.
"Activity equivalent information is an interesting concept and the role it could play in driving meaningful behaviour change is certainly worth exploring. The potential effectiveness of these types of measures needs to be studied. EU rules which dictate what companies can and cannot put on their food labels would need to be considered in any proposals to add to on-pack information”
Make it meaningful
The independent charity, Royal Society for Public Health (RSPH), has been campaigning for exercise labels on food and drink in the UK.
It commissioned a survey of over 2,000 adults last year which found that 63% supported exercise labels while 53% said it would help them make “positive behavioural changes”.
Its CEO Shirley Cramer said: “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.”
“Given the responsibility of the food industry in tackling the obesity epidemic, we believe activity equivalent calorie labelling could provide the nudge many people need to be more active and support their customers to make healthier choices.”
In 2014, more than 60% of UK adults were overweight or obese.
Source: Appetite Journal
First published online, http://dx.doi.org/10.1016/j.appet.2017.01.007
“The influence of calorie and physical activity labelling on snack and beverage choices”
Authors: U. Masic, P. Christiansen and E.J. Boyland