MONDAY, May 9, 2022 (HealthDay News) -- America's kids have a weight problem, but regulations that boosted the nutritional standards for school meals may have helped slowed down weight gain among low-income students, a new study finds.
For decades, the National School Lunch Program has provided free or low-cost meals to U.S. schoolchildren. As of 2016, more than 30 million students nationwide were participating, according to government figures.
In 2010, a federal law was passed to strengthen the nutritional requirements of those school meals, aiming to increase children's intake of fruits, vegetables, fiber-rich grains and unsweetened beverages.
The move came in response to a worrisome trend: U.S. children who participated in the meal program were, on average, gaining more weight than their peers who were not in the program.
"There was a lot of concern at the time that participation in the school lunch program was contributing to obesity," said Andrea Richardson, the lead researcher on the new study.
Since the new standards were implemented, research has pointed to positive effects -- namely, that diet quality improved for kids in the program.
What's been unclear is whether that has had any effect on weight trajectories.
The new findings, published May 5 in JAMA Network Open, suggest it has. Among children who entered kindergarten in 2010-2011, those in the school lunch program were no longer gaining weight more rapidly through their elementary school years, versus their peers.
The fact that the gap closed is good news, according to Richardson, a policy researcher at the nonprofit research organization RAND Corporation.
But not all of the findings were encouraging. In recent years, children overall have been entering kindergarten at a higher body mass index (BMI) than their counterparts two decades ago. And by fifth grade, 17% of all children in the recent group fell into the obesity category, while nearly 10% had severe obesity.
So while the results point to benefits from more nutritious school meals, the issue of childhood obesity needs to be addressed on multiple fronts.
"Schools are powerful places to intervene," Richardson said. But at the same time, she added, obesity is complex, and efforts beyond the school walls are important, too.
The findings are based on a nationally representative sample of 3,388 children who entered kindergarten in the 1998-1999 school year and 2,570 children who started in 2010-2011.
In the earlier group, low-income children in the school lunch program gained weight more rapidly than their peers through fifth grade, with their average BMI being closer to the obesity threshold for children.
Among children in the more recent group, that gap was erased.
"It isn't surprising this study found what it did," said Leah Carpenter, associate director of the Gretchen Swanson Center for Nutrition, a nonprofit research institute. "In our research, I could see the difference [the new standards] were making as far as what was ending up on children's plates."
Carpenter, who was not involved in the new study, said it adds evidence on students' weight trajectories that had been lacking before.
Dr. Dariush Mozaffarian has also found that school meals became more nutritious after the 2010 law. In a recent study, his team showed that in 2018, school meals were actually the healthiest meals most U.S. kids were getting all day.
But school meals also accounted for only 9% of kids' daily calories, on average, said Mozaffarian, dean and professor of nutrition at Tufts University's School of Nutrition Science and Policy.
So it's "asking too much of schools" to expect them to change the course of childhood obesity, he said.
The quality of food from other sources, including grocery stores and restaurants, needs to be addressed, according to Mozaffarian. And the onus should not be on parents, he said: They need help from policies that make healthy food choices more accessible and affordable.
Meanwhile, many schools are struggling to maintain the nutritional strides made since 2010. The pandemic has "disrupted everything," Carpenter pointed out.
Prior to the pandemic, many schools had adopted or were moving toward making meals "from scratch," rather than heating up packaged food, for example.
"But supply-chain issues and staffing [shortages] are still huge barriers," Carpenter said.
"Some schools that were on a path toward scratch cooking have had to take a step back and put it on pause," she added.
It does seem clear that when children are offered healthier meals, they will eat them.
One argument against the 2010 nutrition standards had been that kids might turn their noses up at the new options, and some might drop out of the school lunch program altogether.
But, Richardson said, other research has shown that was not the case.
The American Academy of Pediatrics has advice on nutrition and exercise.
SOURCES: Andrea Richardson, PhD, MPH, policy researcher, RAND Corporation, Pittsburgh; Leah Carpenter, MPH, associate director, Gretchen Swanson Center for Nutrition, Omaha, Neb.; Dariush Mozaffarian, MD, dean, professor, nutrition, Friedman School of Nutrition Science and Policy at Tufts University, Boston; JAMA Network Open, May 5, 2022, online