The new rules will take effect during the 2017-2018 school year.
"I wouldn't be as big as I am today without chocolate milk," Perdue said in his remarks to reporters.
"We're not winding back any standards at all," Perdue said. "We are just slowing down the process."
"I applaud former First Lady Michelle Obama for addressing those obesity problems in the past," he said.
Perdue recalled hearing from many students who have complained about fat-free and reduced fat chocolate milk offered in schools. In light of these "palatability issues" Perdue said he decided to make a change.
"This is not reducing the nutritional standards whatsoever," he said.
"Try eating a biscuit made with whole grains," Roberts said. "It just doesn't work!"
Just before the remarks, the two sat for a meal with Catoctin Elementary students on long lunch tables and munched on fruit, carrots and some bread out of a lunch tray.
"What do you do as Secretary of Agriculture?" a student asked.
"We try to keep your food safe!" Perdue responded.
Perdue's new interim rule is meant to provide “regulatory flexibility” for the National School Lunch Program, which is a federally assisted meal program that provides nutritionally balanced reduced-cost or free lunches to children.
The law requires that students are offered fruits and vegetables every day, have whole grain-rich foods, fat-free or low-fat milk, and have meals with reduced sugars and sodium.
Republicans, farmers and school groups have long since lobbied for lunch reform, saying the current rules are overly restrictive and costly to implement.
According to USDA figures, school food requirements cost school districts and states an additional $1.22 billion in Fiscal Year 2015.
During the remarks, a small group stood outside the school to protest the Secretary's remarks.