Is the Michelle Obama-approved school lunch initiative working?

When healthier food standards were implemented in 2012, skeptics voiced concern that fewer students would be eating lunch at school. But now a new study has not only dismantled that notion but also found meals at school have indeed become more nutritionally wholesome.

Signed into law in 2010, the Michelle Obama-approved Healthy Hunger-Free Kids Act (HHFKA) increased portions of whole grains, fruits, and vegetables, and limited the number of calories in school breakfast and lunch. The US Department of Agriculture standards were implemented starting in the 2012-2013 school year, affecting up to 31 million students in the National School Lunch Program.

In a report published Monday in the journal JAMA Pediatrics, researchers from the University of Washington Nutritional Sciences Program concluded that the meal standards have had substantial impact on the quality of food.

"This is, in my mind, really verification that implementing these changes are first of all doable," Donna B. Johnson, lead author and a professor at the University of Washington, told CNN.

Looking at the nutrition value of 1.7 million meals selected by 7,200 students in three middle and three high schools in an urban school district in Washington state, the scientists compared data collected in the 16 months before the standards were carried out with data collected in the 15 months after implementation. They found that there was an increase in six nutrients: calcium, vitamin C, vitamin A, iron, fiber, and protein.

Measuring empirical values by using the meals’ mean adequacy ratio (MAR), they calculated that nutritional quality increased by nearly 30 percent, from a MAR of 58.7 before the Healthy Hunger-Free Kids Act to 75.6 after implementation. Calorie intake also changed – the energy density ratio was 1.65 before HHFKA compared with 1.44 after.

The changes can be largely attributed to the increase of fruits and vegetables, the researchers write.

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

A bigger feat, however, was suggested by data showing that meal participation has barely changed. In the school district that the study examined, the number of students who ate lunch at school declined by only one percentage point after the new standards, from 47 percent to 46 percent.

Meal participation is one of the biggest points of criticism for HHFKA. The School Nutrition Association and the School Superintendents Association, for instance, are among groups opposed to HHFKA because they believe the act has caused fewer students to eati meals at school and has driven up the cost of food.

The Government Accountability Office found in September that participation in the national school lunch program declined by 4.5 percent, or 1.4 million students, from the 2010-2011 school year through 2013-2014.

“We commend these six schools JAMA followed who have maintained student participation in meal programs, but the study ignores the unintended consequences causing nationwide decreased participation in the [National School Lunch Program],” Jean Ronnei, president of the School Nutrition Association, told Time magazine in the statement.

The NSA does, however, support the HHFKA’s cap on calories and supplementation of nutrition.

Ms. Johnson and her colleagues acknowledged limits in their research, including the fact that the study only analyzed food that students selected, not food consumed. But they point to previous research that suggests plate waste has not gone up since the standards were made.

"We tend to eat more if larger portions are put in front of us and if there's more variety," Johnson said. "We can use that to our advantage to nudge people along to make good choices."

Experts say while the results of the current study may not reflect the way that other school districts across the country have reacted to the new lunch policies, other data is expected to emerge in the next year to confirm or negate this study’s findings of progress.