When you go to a restaurant, you may well be presented with a wide array of dishes, each printed on a menu alongside its calorie content. A chicken burger and fries may come to 1597 kilocalories. Swap the meat for a plant-based substitute, and it could rise to 1746 kcal. Opting for the vegan bacon ketchup adds another 300 kcal.
Since 2022, these calorie labels have been compulsory for any restaurant, caf茅 or takeaway chain in England with more than 250 staff, as part of an anti-obesity campaign launched in 2020 by the government of former UK prime minister Boris Johnson. Yet the benefits to public health are contentious, with emerging studies raising serious questions about the assumed effects on consumer behaviour.
鈥淭he idea is that having more information means that people will make better decisions,鈥� says at the University of Cambridge. 鈥淏ut there may be so many other, potentially stronger, effects that are going to affect their decisions. People may think about, say, value for money rather than lower calories.鈥�
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England鈥檚 policy follows the US鈥檚 example. New York City took the lead in 2008 and, a decade later, across the country in any chain restaurant with more than 20 locations. A study from 2018 suggested that people chose slightly lower calorie meals as a result, with an 鈥� which makes up around 2 per cent of the daily recommended calorie intake for a man and 2.5 per cent for a woman.
Using this figure, at the University of Liverpool in the UK and her colleagues recently constructed a mathematical model to predict the long-term consequences of the policy for the body mass index and cardiovascular risk of people in England over 20 years. The results predicted a in the prevalence of obesity, and 730 fewer deaths from cardiovascular disease by 2041.
This may seem like a small effect, especially given that 830,000 cardiovascular deaths are expected over that period, but Colombet says it shouldn鈥檛 be totally discounted. 鈥淩educing obesity and preventing deaths cannot be disappointing for me, especially for a policy that does not seem to increase health inequalities nor affect people鈥檚 purchasing power,鈥� she says. The model also suggests that the policy could prevent up to 9200 deaths if it were expanded to include every eatery, not just large chains.
But the UK government may wish to consider other strands of evidence before expanding the policy in England. , also at the University of Liverpool, worked with Essman and their colleagues to survey 3000 diners before the legislation was introduced and another 3000 people afterwards. They found that having calories on menus made .
There may be a moral argument for making people aware of what they are purchasing and eating, says Essman. 鈥淏ut people may need more support in order to use the information.鈥� For example, menus could include infographics that illustrate what a balanced meal looks like, he says.
Information is also only useful if it is accurate. The guidelines require the calorie counts to lie within a 20 per cent margin of error, but a study by , also at the University of Liverpool, Polden and their colleagues, showed that 35 per cent of the calories printed on sampled menus .
The errors included both under- and overestimations, which may have come about due to variations in portion sizes or the methods used to calculate the content. There is no reason to believe that outlets are deliberately misleading consumers, but this uncertainty may reduce the public鈥檚 trust in the policy, says Finlay.
Its potential to reduce obesity should also be balanced against the damage it may cause to people with eating disorders. A 2017 study found that calories on menus may make people with anorexia or bulimia , whereas people with binge eating disorder may be more likely to order meals with more calories.
鈥淧eople are talking about how they now feel like they can鈥檛 go into certain restaurants because they fear that it will set back their recovery,鈥� says at the UK eating disorders charity Beat.
Whether the new UK government will refine the policy in England remains to be seen, but such research may influence other nations. The Scottish government, for instance, to introduce mandatory calorie labels while it appraises the long-term consequences.
When the stakes for physical and mental health are so high, the public deserves a decision based on the strongest science rather than assumptions. 鈥淵ou could say that the policy is a step in the right direction, but we need a better understanding of the ways that people are interacting with that information,鈥� says Essman.
