A much–delayed U.S. rule requiring restaurants and retailers to clearly display food calorie counts has been pushed back again, and could be rewritten or scrapped as the Trump administration rebuffs Obama–era regulations.

Notice came shortly after the U.S. Department of Agriculture relaxed some school lunch rules that were part of former first lady Michelle Obama's signature effort to fight childhood obesity.

The Food and Drug Administration late on Monday extended the compliance date for the calorie labeling rule from May 5, 2017, to May 7, 2018, to enable further consideration of ways to cut costs and make requirements more flexible.

The rule was designed to help U.S. consumers, who eat and drink about one–third of their calories away from home, battle the bulge. It is part of the Affordable Care Act of 2010, also known as Obamacare, which the Trump administration has vowed to repeal and replace in a bid to slash regulations it considers harmful to business.

Health and Human Services Secretary Tom Price, who oversees the FDA, said in a statement his agency believed in promoting sound nutrition and applauded the delay.

"Imposing burdensome rules that leave business managers and owners worried about harsh potential penalties and less able to serve their customers is unwise and unhelpful," Price said.

The rule's opponents, including Domino's Pizza Inc, movie theater operators, and convenience and grocery stores, have pushed for delays over the years.

But even if the calorie disclosure rule is killed at the federal level, it is unlikely to go away.

Chains like Panera Bread Co and McDonald's Corp, have been displaying such information for years in compliance with rules set by California, New York City and other jurisdictions.

Panera in 2010 became the first national chain to post calorie counts for its salads, sandwiches and pastries.

Sara Burnett, Panera's director of food policy and wellness, said customers want to know what is in the food they eat, so the chain will continue to comply with the federal law as it was written.

"It's information that helps our guests make informed decisions," Burnett said.

—Lisa Baertlein