They may have been made with love, however, according to a study, home-packed lunches lose out to school lunches in terms of overall nutritiousness.

Published in the Journal of Nutrition Education and Behavior, the study was carried out by researchers from Virginia Tech University. It compared 560 home-packed meals with over 750 school lunches served to pre-K and kindergarten students across three schools, tracking nutritional values for more than five days using the 2012-2013 National School Lunch Program Standards as a guide.

According to the study, home-packed lunches paled in comparison to school meals because they offered lower nutritional quality. This was mostly because home-packed meals had more fat and more calories, no thanks to more sugary drinks and desserts that parents pack in for their children. Home-packed lunches were also higher in vitamin C and iron but it was lower in nutrients like vitamin A, calcium, protein, and fiber.

There are around 50 million children attending public elementary and secondary schools in the U.S. every day. Out of that number, about 40 percent bring their own food to school while the other 60 percent rely on school lunches for sustenance during the day.

On average, school meals had around 512 calories while home-packed lunches packed in about 608 calories. School meals also had around 26 grams of protein while home-packed lunches offered only 18 grams.

Where school lunches had more fruits, vegetables, milk, and sugar-free juice, home-packed meals featured more snacks like crackers and chips. The only notable advantage that home-packed meals had over school lunches was that the former had less sodium, clocking in at 880 mg whereas the latter had around 1,000 mg.

University nutrition director at St. Louis' Washington University Connie Diekman was not surprised at the results of the study.

"This study provides outcomes that are similar to other studies that show the positive benefits of school lunch. While it is surprising to see the higher sodium content in the school lunch, the nutritional pluses of the school lunch -- more fiber, vitamin A and less sugar and saturated fat -- make the [nutritional] value aspect of school lunch better," Diekman said.

To make home-packed lunches more nutritious, she advises parents to include protein, dairy, vegetable, and fruit. If packing a sandwich, add in carrot sticks and an apple. For dairy, include something that the child likes, such as cheese, milk or yogurt. To keep the dairy cold, making it likely to be consumed by the child, put in a cold pack if possible.