Food waste is a big problem in public schools. According to one study, half-eaten sandwiches, picked-at salads, not-enough-time-to-finish-munching-them carrot sticks and other lunch box fare make up nearly 24 percent of the total waste generated in K-12 schools throughout the United States.

Related: 9 Ways to Prevent Food Waste

What's an environmentally conscious parent to do? For my part, I try to keep an eye on how much my children eat at home and pack lunch portions accordingly. My 10-year-old rarely eats a whole sandwich, for example, so I send him to school with a half. Other food that comes back uneaten I designate as an afternoon snack, rather than allow my kids to rip into a fresh bag of chips or desecrate a bunch of grapes.

Related: How to Cook (Safely) with Kids

Schools can help solve the food waste problem too. For example, in cafeterias with vending machines kids often opt for junk food rather than healthier fare brought from home. (The California Department of Education calls these vended items " competitive foods.") Removing vending machines from school cafeterias could help cut food waste tremendously.

In the infographic below, the Department of Agriculture (USDA) outlines other initiatives that schools can take to reduce food waste. I especially love the USDA's suggestion about making lunch periods longer. So many times the answer I get when I ask one of my kids why there's uneaten food in his or her lunch is, "I didn't have time."

Related: 3 Healthy School Snack Recipes

Seems to me we can give our children ten extra minutes to eat. It's true a mind is a terrible thing to waste. But so is an entire PB&J. 

food waste infographic(Photo: United States Department of Agriculture/USDA)