FRIDAY, Aug. 26, 2016 (HealthDay News) -- If kids help plan and prepare their school lunches, they're more likely to eat them, an expert says.

Give children a list of choices in each of the main food groups -- fruits, vegetables, whole grains, lean protein and low-fat dairy -- and let them pick favorites in each category, Penn State University dietitian Kara Shifler suggested.

"This definitely takes time, but past third or fourth grade, they should be taking on some of the responsibility themselves. That will help them have more control over what they eat and be more experimental in the kitchen," she said in a university news release.

Pre-planning a menu and shopping for the entire week will reduce how much time parents have to spend packing a healthy lunch on busy weekday mornings, Shifler said.

Her colleague, Dr. Marsha Novick, recommended packing a rainbow of fruits and vegetables.

"Look for things that are quick -- that you can easily grab and put into baggies like baby carrots, cherry tomatoes and sugar snap peas. That can help with the time pressure we all face in the morning. It's also helpful to pack some of it the night before," said Novick, director of the pediatric weight loss program at Penn State Children's Hospital.

Other healthy choices include dinner leftovers such as soup with vegetables and pasta with vegetables in the sauce, Novick said in the news release.

While a home-packed lunch is often best, school cafeterias now offer a fruit, vegetable, whole grain and low-fat dairy item at each meal.

"The key is to know what is on the menu for each day and discuss the choices with your child ahead of time," Novick said.

More information

The U.S. National Institutes of Health has more on school day breakfasts and lunches.