Schools will not have to cut the salt in meals just yet and they can serve kids fewer whole grains, under changes to federal nutrition standards announced on Monday.

The move by the Trump administration rolls back rules championed by former first lady Michelle Obama as part of her healthy eating initiative.

As his first major action in office, Agriculture Secretary Sonny Perdue said the department will delay the requirement on lowering the amount of sodium in meals while continuing to allow waivers for regulations that all grains on the lunch menu must be rich in whole grains. That means that they are more than half whole grain.

Schools could also serve 1 percent milk instead of the nonfat now required.

"If kids aren't eating the food, and it's ending up in the trash, they aren't getting any nutrition - thus undermining the intent of the programme," said Perdue, who travelled to a school in Leesburg, Virginia, to make the announcement.

Perdue, a former governor of Georgia, said some schools in the South have had problems with grits, because "the whole grain variety has little black flakes in it" and kids would not eat it.

"The school is compliant with the whole-grain requirements, but no one is eating the grits," Perdue said. "That doesn't make any sense."