Changes to the national school lunch program in the last decade that cracked down on sodium and fat content in school meals and required more fruits and vegetables could have reduced children’s likelihood of becoming overweight, according to a new research paper.
In 2010, as education advocates sounded the alarm over increasing childhood obesity—a health condition that can have major long-term consequences for young people—lawmakers passed a bill allowing the U.S. Department of Agriculture to overhaul the National School Lunch Program for the first time in decades. The department’s new rules under the Healthy, Hunger-Free Kids Act set minimum nutrition standards for school meals and reduced portion sizes. The rules also called for more fruits, vegetables, and whole grains, and limited sodium, sugar, and fat.
While the Trump administration initially gave schools more time to comply with those Obama-era rules before attempting to largely roll them back, school meals changed, and those changes have likely made a difference, the research found. The conclusion potentially offers hope after the U.S. Centers for Disease Control and Prevention found last year that childhood obesity had gone up over the course of the COVID-19 pandemic as kids spent more time on screens and less time exercising.
“One thing is clear from the research, and that is that it really is helpful—the improvements to school meals have really made a difference,” said Geri Henchy, director of nutrition policy for the Food Research & Action Center, an anti-hunger advocacy group.
Before the new nutrition standards, participation in school meal programs had been linked to higher rates of obesity due to fatty, carbohydrate-packed choices. But the new working paper published last month by researchers at Northwestern University finds little proof that participation in school meal programs after the federal government tightened nutrition standards led to weight gain.
“These results suggest that improvements in the nutritional content of school lunches have been largely successful in reversing the previously negative relationship between school lunches and childhood obesity,” the researchers concluded.
School meals reach lots of kids
To assess whether school meals make children more or less likely to become obese, the researchers evaluated data on the quality of school meals between 1991 and 2010, before the Obama administration’s tighter nutrition standards took effect. They then tracked a nationally representative group of children from when they entered kindergarten in 2010 and completed 5th grade in 2016, controlling for children who already entered kindergarten overweight.
That period covered the start of the stricter nutrition standards, which were largely phased in over a three-year period starting with the 2012-13 school year.
It is difficult to detect whether a single change in children’s lives has much of an impact on childhood obesity, the researchers acknowledged, but school meals are a key policy lever simply because of their reach.
“The National School Lunch Program (NSLP) serves meals to over half of the nation’s school-aged population each school day, so improvements to the nutritional quality of school meals could have important impacts on obesity—particularly in light of research that found participating in school lunch increased children’s caloric intake and body weight,” the report said.
The researchers, Therese Bonomo and Diane Whitmore Schanzenbach, analyzed two waves of school lunch menus prior to and after the nutrition guidelines were changed. They found that the number of calories served per meal was generally lower in the later wave of menus, regardless of school characteristics.
Then, they estimated the relationship between school lunch participation and the rate of students’ weight gain from the beginning of kindergarten through 5th grade.
After the nutrition standards changed, they found, students who ate school lunches were no more likely to be overweight than students who brought their food from home.
“This indicates that there were substantial changes in content of school lunches over time, perhaps due to [the changes] and/or the momentum leading up to it,” the report concludes. “Thus, there is reason to believe that the relationship between school lunch participation and obesity may have also changed.”
From Obama to Trump to Biden, uneven implementation
Despite its apparent success, the implementation of the Healthy, Hunger-Free Kids Act has faced a rocky road.
The changes the legislation brought on were initially met with some criticism and resistance, as students across the country took to social media to criticize the smaller portion sizes and different food choices.
One video Kansas high school students produced—a parody song called “We Are Hungry” to the tune of the song “We Are Young” by Fun—racked up more than 1.5 million views on YouTube and caught the attention of national policymakers. Even more students complained on platforms like Twitter under the hashtag #ThanksMichelleObama.
Some research found there was more food waste following the rollout of the new nutrition guidelines, while other research came to the opposite conclusion. Participation in school lunch programs also decreased as the new guidelines were implemented, USDA data show.
The Trump administration relaxed the Obama-era nutrition standards on milk, sodium, and whole grains after it took office in 2017 before attempting to largely roll them back the next year.
Then, in 2020, the Trump administration announced plans to further roll back the nutrition guidelines, targeting the fruit and vegetable requirements, to allow schools more flexibility and reduce food waste, USDA officials said at the time.
Soon after, a federal judge overturned the 2018 Trump rollback, finding the final rule differed too much from the version the Trump administration put out for public comment.
Earlier this year, the Biden administration announced plans to limit school meals’ sodium and sugar content and require that school meals primarily contain whole grains, detailing a phased implementation of the rules to give schools more time to comply, largely due to complications caused by the COVID-19 pandemic, FRAC’s Henchy said.
“It hasn’t progressed in a straight line—there’s been a lot of back-and-forth,” Henchy said. “But we’re moving forward again.”
