The rule is intended to make calorie information as obvious as possible to consumers before they order.

The group opposed New York state's move to require food chains to post calorie information on their products.

Panera Bread was the first in its industry to post calorie information voluntarily at all company-owned cafes.

July 26, 2011 - A new study suggests many customers of fast-food restaurants aren't taking advantage of calorie information provide on some menus.

About 15% of people who buy fast food in New York City read the calorie information required on menus, the study shows.

They questioned whether the rule would discourage restaurants that have not already provided calorie information from doing so.

Industry officials also say that in many instances it would be impossible to provide accurate calorie information for all the possible variations of a dish.

Some fast-food purveyors will provide calorie information on request, but even that can be hard to understand.

This saw the introduction of calorie information on Domino's main ordering website.

But how efficient is the provision of calorie information as a deterrent to eat and drink unhealthily?