It has been sold as a solution to the obesity crisis, to make us all more aware of our waistlines.
But calorie counts on restaurant menus may not work as well for men, who find them easier to ignore.
A study has found women are far more likely to slash their calorie intake if menus clearly show what each meal contains.
They order meals with 75 fewer calories, while the average for both sexes is just 45 calories.
There is no British rule requiring restaurants to display calories, despite calls from health campaigners to make them compulsory.
A study has found women are far more likely to slash their calorie intake if menus clearly show what each meal contains
However, some companies including McDonald’s and Starbucks do so voluntarily, and the effect on people’s behaviour has been measured in a review of 186 studies led by the University of Technology Sydney.
The Australian researchers found women were ‘more responsive’ than men when it came to the menus, and called for additional research to determine why.
The menus also worked better for people who were overweight, who slashed 67 calories on average from their choice of meal.
Lead researcher Natalina Zlatevska said the calorie reduction could make a real difference for those who eat out regularly, adding: ‘With more and more food dollars spent on meals purchased outside the home, anything we can do to educate consumers, and make them a bit more aware of their choices is a good start.’
The latest figures from the UK show more than a quarter of adults and a fifth of children eat food from restaurants and takeaways at least once a week.
The problem is that eating out often means consuming more fatty, sugary and salty food.
More than 1.6 million meal choices were studied by the Australian researchers across 186 research papers on how calories in menus affect behaviour.
They found people shown calorie counts were more likely to cut their consumption in table-service restaurants and when eating lunch rather than dinner.
The study, published in the Journal of Retailing, states: ‘It could be that individuals are more likely to notice calorie information on a menu during a sit-down meal, and when they are more likely to be making individual choice selections, such as at lunchtime.’
More than two-thirds of the 186 studies reviewed showed people cut their calories when they could see them clearly listed – by an average of 27 calories per meal.
The results ranged from one calorie to 400 calories across the various trials.
From next year, restaurants in the US will have to display calories and the study states: ‘Supporters of the legislation argue that consumers are often unaware, or underestimate, the nutritional content of the food they are purchasing.’
A leaked draft version of the UK Government’s child obesity strategy contained a similar compulsory requirement.
It said: ‘We will require calorie labelling for restaurant, café and takeaway menus to make the healthy choice clearer.’ However the final childhood obesity plan removed all trace of this.
A Department of Health spokesman said: ‘We know people consume too many calories—that’s why Public Health England are embarking on extensive calorie and sugar reduction programmes, to make foods healthier before they hit plates and shelves. Already big businesses like Tesco, Nestle, Britvic and the makers of Ribena and Lucozade are rising to the challenge.
‘This is just one part of our childhood obesity plan, the most ambitious of its kind anywhere in the world.’