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.