Still, by most accounts, school lunches in America are better than they have been in decades. Cooking from scratch is on the rise, salad bars have been added to tens of thousands of schools and a federally supported farm-to-school program is operating in 42,500 schools.

“We have been through a period of big changes, and there are a lot of people who don’t like big changes,” said Dayle Hayes, an author and school nutrition educator in Montana. “But what we need to remember is that what schools are doing reflects the broader food trends in this country. It is just getting better by the day everywhere.”

Many questions remain, though. Here are answers to a few:

Has the Trump administration begun to dismantle the Obama initiatives?

Much was made about changes to the federal school-food rules that Mr. Perdue announced in May after taking over the Department of Agriculture. But the changes (to rules set forth as part of the 2010 legislation) are actually quite minor.

“What he said didn’t change anything, honestly,” Ms. Hayes said.

The changes fall into three areas. The first involves how much whole grain the federal government requires in school meals that qualify for at least some federal reimbursement. Under rules set by the Obama administration, buns, pasta and other foods made from grain must be at least half whole grain. Districts can apply for exceptions, which are especially popular with regional foods that are traditionally made with white flour.