School lunch programs feed more than 31 million public school students each day, giving them the opportunity to impact nutrition on a grand scale. In 2010, President Barack Obama signed the Healthy, Hunger-Free Kids Act (HHFKA), a bill designated to fund child nutrition programs and free lunch programs for five years. As Americans enter into 2016, researchers from the University of Washington Nutrition Sciences reviewed how the program has affected youth health.

The study, published in the Journal of the American Association (JAMA) Pediatrics, analyzed the changes in more than 1.7 million lunches at three middle schools and three high schools in a city school district in Washington State between 2011 and 2014. They measured the meals' "mean adequacy ratio" (MAR) by calculating how energy dense the food was (fewer calories per gram is optimal for weight loss) and the amount of nutrients it provided (calcium, vitamin C, vitamin A, iron, fiber, and protein). The higher the MAR measurement, the better quality the food was for children and adolescents.

Before the $4.5 billion act was implemented, researchers calculated the food to be 58.7 MAR. Within three years, the MAR increased to 75.6, improving its nutrition significantly. The amount of low-calorie foods increased, making the energy density drop from an average of 1.65 down to 1.44 after the act was implemented.

"We found that the implementation of the new meal standards was associated with the improved nutritional quality of meals selected by students," the study's author wrote. "These changes appeared to be driven primarily by the increase in variety, portion size, and the number of servings of fruits and vegetables."

School lunch programs are a vital necessity in many children's lives. For some children, it's the only meal they eat in the entire day. According to Share Our Strength, a national non-profit dedicated to ending childhood hunger, 65 percent of teachers reported most of their kids rely on school meals as their primary source of nutrition, while 86 percent said students come to school hungry.

To qualify for free lunch, students' families must have incomes at or below 130 percent of the poverty line (an average of $28,665 for a family of four). Families who fall between 130 to 185 percent below the poverty line (average of $40,793 for a family of four) qualify for reduced price lunches, which mean they cannot be charged more than forty cents per lunch.

The opportunity to feed children nutritious meals when they need it most should not be missed if America wants to raise healthy children. The HHFKA was considered such a success that in 2015, California extended the program into the summer to continue feeding children year round.

"The HHFKA created significant improvements in school nutrition, but that progress is now at risk of repeal," wrote Erin R. Hager, a professor at the University of Maryland's School of Medicine, along with Lindsey Turner, a professor at Boise State University, in an accompanying editorial. "We encourage policy makers to consider the hard evidence rather than anecdotal reports when evaluating the impact of policy changes. It is worth celebrating the successes of the HHFKA, rather than abandoning the recent progress made in keeping our nation's children healthy."

Source: Johnson DB, Podrabsky M, Rocha A, and Otten JJ. Effect of the healthy Hunger-Free Kids Act on the Nutritional Quality of Meals Selected by Students and School Lunch Participation Rates. JAMA Pediatrics. 2016.

Successes of the Healthy Hunger-Free Kids Act. Hager ER and Turner L. JAMA Pediatrics. 2016.