New research links food calorie labeling to small reductions in selection and consumption

When applied at scale, UK researchers say food calorie labeling could lead to “potentially meaningful impacts” on population health. After reviewing 25 randomized control trials, the team found that calorie labeling led to small reductions in calories selected (1.8%) and consumed (5.9%).

The researchers say the evidence is most substantial when considering product purchases, but that evidence for consumption suggests a similar effect. They caution that insufficient evidence exists to estimate the impact of calorie labeling on alcoholic drink consumption. 

Calorie labeling has been mandatory in England’s out-of-home food sector since April 2022. The policy is part of the UK government’s strategy to tackle obesity. Businesses with over 250 employees must prominently display the kilocalories associated with each meal option. 

“Our review suggests that calorie labeling leads to a modest reduction in the calories people purchase and consume,” says senior author Dr. Gareth Hollands from the University College of London’s Social Research Institute, UK. 

“This may impact health at the population level, but calorie labeling is certainly no silver bullet. Our previous version of this review from 2018 reported a potentially larger effect but was inconclusive because there was significant uncertainty over the results.”

“This update has reduced that uncertainty, and we can now confidently say there is very likely a real, albeit modest, effect.”

Mandatory labeling

The review of 25 randomized control trials emphasizes real-world settings, with 16 studies conducted in restaurants, cafeterias and supermarkets. The study, published in Cochrane, includes over 10,000 participants from high-income countries, such as Canada, France, the UK and the US. 

These studies compared the effects of labeling products versus not labeling on the selection and consumption of food and beverages. 

Dr. Hilda Mulrooney, a reader in Nutrition & Health at London Metropolitan University, UK, commends the study’s quality and focus on real-world settings. She was not part of the research team. 

The average reduction in calorie selection was 1.8%, equal to 11 calories in a 600 calorie meal or around two almonds.“The findings for selection were derived from 16 studies, which included 9,850 participants, while those for consumption were based on eight studies, which included 2,134 participants.  Given the strong links between poor diet and ill health, these are important findings.” 

“Tools such as nutrition labels provide guidance for consumers to help them make informed choices and to compare options for purchase and consumption, essential given the high proportion of pre-packaged and pre-prepared foods in most diets,” Mulrooney adds. 

Long-term health benefits?

Tom Sanders, professor emeritus of Nutrition and Dietetics at King’s College London, UK, notes that the small calorie intake reduction observed in the Cochrane review may not have a long-term impact on body weight due to compensatory physiological mechanisms that maintain a constant energy balance. Sanders is not part of the research team. 

“Weight gain normally occurs after large increases in calorie intake, often over a short period (e.g., festive occasions such as Christmas). Similarly, weight is only lost when there are prolonged reductions in calorie intake, usually well over 200 kcal per day,” he says. 

“A further limitation is that it is well known that consumers get fatigued from calorie labeling in the long term, particularly for regularly purchased products. However, calorie labeling can be helpful for individuals who want to control their calorie intake, particularly when consuming food outside the home.”

In addition, research indicates that nutrition labels that include information in addition to calories, such as serving size and nutrients, support healthier eating habits. 

The authors call to combine calorie labeling with policies for the food industry, such as marketing restrictions or reformulation.Wider policies needed

The authors and experts highlight that calorie labeling alone cannot address chronic diseases like obesity. Last year, a University of Liverpool, UK, study found that mandatory labeling did not lower calorie consumption. However, the authors say it may lead to a broader public health impact when combined with other health policies. 

Moreover, researchers from the same university caution that mandatory calorie labeling may harm people with an eating disorder. The team suggests businesses also provide calorie-free menus for people who may find seeing calorie information on menus challenging. 

Hollands agrees that calorie labeling remains “somewhat contentious” in terms of whether it has any effect and whether potential benefits outweigh risks or harms. The authors say studies on possible harms, such as mental health impacts, lack data and recommend further research. 

“We can now say with considerable confidence that it does have a small but potentially meaningful effect on people’s food choices,” says Hollands. “Labelling may therefore have a useful role, ideally alongside a broader set of approaches that place more onus on the industry than individuals, such as taxes, marketing restrictions and reformulation.”  

He cautions: “We should not expect miracles, and any implementation of calorie labeling must balance the many potential positive and negative impacts of such policies.”