"We are going full steam ahead to making sure that the school day is healthier," Concannon told reporters.
The new guidelines, which take effect this school year, create a maximum-calorie measure for student lunches based on age and grade in addition to reform menus. Previously regulations only established a minimum-calorie benchmark.
"This is an important milestone in school health," said Sam Kass, a White House chef and senior policy adviser for healthy food initiatives. "It is so critical that when parents send their kids off to school they know they have the energy and strength to learn."
Childhood obesity has been a leading cause for Michelle Obama, who has come under fire from conservatives who argue hers is a "nanny state" approach to promoting better health.
The new standards were created under the Healthy Hunger-Free Kids Act, which President Obama signed into law in 2010.