Patrick McCoy (right) and Harry Fowler of Schwan's Food Service show off their company's Big Daddy's pizza at the School Nutrition Association's national conference in Chicago in 2007. Brian Kersey/AP hide caption

itoggle caption Brian Kersey/AP

Suzy Amis Cameron, wife of director James Cameron, and gardener and educator Paul Hudak inspect seedlings in the MUSE School CA greenhouse in Calabasas, Calif. Amis Cameron, who founded the school with her sister, wants the school menu to be entirely plant-based by fall 2015. Eliza Barclay/NPR hide caption

itoggle caption Eliza Barclay/NPR

Currently, half of all products served in the school lunch program must be "whole-grain rich," which USDA defines as products made of at least 50 percent whole grain. According to the new standards, by the start of the next school year, schools must use only products that are whole-grain rich. Rogelio V. Solis/AP hide caption

itoggle caption Rogelio V. Solis/AP

First lady Michelle Obama has been doing a lot of high-fiving with schoolchildren like these in Dallas to promote healthful lifestyles. Now she's diving more deeply into the politics of school lunch. LM Otero/AP hide caption

itoggle caption LM Otero/AP

Michelle Obama eats lunch with school children at Parklawn Elementary School in Alexandria, Va., in 2012. The first lady unveiled new guidelines Tuesday aimed at cracking down on the marketing of junk food to kids during the school day. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

When schools close for bad weather, some kids miss out on much-needed nutritious meals. "It's hard to be a hungry person, and it gets harder when the weather is like this," Nancy Roman, president of the Capital Area Food Bank in Washington, D.C., says of severe cold and snow. Jessica Glazer/NPR hide caption

itoggle caption Jessica Glazer/NPR

Uintah Elementary School in Salt Lake City, where up to 40 students were served lunch Tuesday — only to have it discarded. They were told they didn't have enough credit on their accounts. Google hide caption

itoggle caption Google

Lunch at the West Salem School District in Wisconsin. Michelle Kloser/ for NPR hide caption

itoggle caption Michelle Kloser/ for NPR

Students pick up their lunch at Barre Town Elementary School on Sept. 3, 2013 in Barre Town, Vt. Toby Talbot/AP Photo hide caption

itoggle caption Toby Talbot/AP Photo

Advocates for healthy food in Virginia schools have met a reversal, after cafeterias changed back to hamburgers with additives due to students' complaints. The schools had been serving all-beef burgers such as these, being grilled at a farmer's market. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images