Students gathered as the chef sliced tomatoes with a plastic knife in a Brooklyn public school cafeteria. Their eyes followed as she held up a slender green cylinder before the crowd of parents and kids in plastic aprons and hairnets.

"What's that?" kids shouted.

"It's a scallion. But don't eat it now," warned Leigh Armstrong, a culinary student and volunteer chef. "It doesn't taste like celery."

Armstrong was helping at Cooking Matters, a free, six-week class that teaches parents and kids how to shop for and prepare healthy, inexpensive meals. The program launched 20 years ago through the nonprofit Share our Strength, and it now serves more than 11,000 families across the country.

Read the full report - 1 in 5 U.S. children at risk of hunger