New York, California, Illinois, Minnesota, New Mexico, Vermont joined the District of Columbia as plaintiffs, saying the changes were arbitrary and capricious.

The Justice Department did not immediately comment.

The lawsuit comes after the Trump administration scaled back contested school lunch standards implemented under the Obama administration, including one requiring that only whole grains be served.

The USDA school lunch program provides low-cost or free lunches in public schools and other institutions. Last year, it served an estimated 30 million children.