The US Food and Drug Administration said it would extend the deadline for chain restaurants to disclose calorie counts on menus by a year to the end of 2016.
The FDA set a national standard for restaurant chains with 20 or more outlets late in 2014, to make people more aware of the risks of obesity posed by fatty and sugary foods as part of the Affordable Care Act.
More than one-third of US adults are obese, according to the US Centres for Disease Control and Prevention.
The calorie rule covers meals at sit-down restaurants, take-out food, bakery items, ice cream from an ice-cream store and pizza, which will be labelled by the slice and whole pie.
They were required to display calories on all menus and menu boards by the end of 2015. Nutritional details, including calories from fat, cholesterol, sugars and protein, must be made available in writing upon request. The rule also includes movie theatres, amusement parks and alcoholic beverages served in restaurants, but not drinks mixed or served at a bar.
At the time of publication in December last year, the FDA had given restaurants one year and vending machine operators two years to comply with the rule.
Since then, industry, trade and other associations, have asked for an additional year to comply, the regulator said on Thursday. To keep the process moving, the FDA plans to issue in August a draft guidance to answer frequently asked questions the agency has received to assist covered establishments in complying with the rule, it said.
Panera Bread Co was the first company to voluntarily display calorie information at all its cafes nationwide in 2010. Others, including McDonald's Corp and Starbucks Corp, followed suit.