A sweeping review of decades of research is challenging a long-standing claim in food policy debates: that federal nutrition assistance programs contribute to childhood obesity.
Researchers at the Washington University School of Public Health and the Brown School at Washington University in St. Louis analyzed 75 peer-reviewed studies spanning more than four decades and found no consistent evidence that children who participate in programs such as SNAP, WIC or school meal programs are more likely to experience unhealthy weight.
“Our review found that the evidence does not support a simple or consistent link between participation in federal food assistance programs and higher rates of childhood obesity,” said Sarah Moreland-Russell, an associate professor at both schools and one of the study’s authors. “Across 75 U.S. studies, we did not see a clear pattern showing that any one federal nutrition program reliably increases or decreases obesity risk in children.”
The findings come as policymakers in several states and at the federal level debate potential restrictions on foods eligible for SNAP benefits and other policy changes aimed at improving diet quality.
The review also examined studies evaluating updates that strengthened nutrition standards — including those under the Healthy Hunger-Free Kids Act — and found either mixed or beneficial effects on children’s weight, with no evidence of harm.
Of the 75 studies examined, 20 showed beneficial associations between participation in nutrition programs and childhood weight outcomes, 32 produced mixed results and 16 found no relationship. Only seven studies reported adverse associations, and those findings were more common in lower-quality research, Moreland-Russell said.
“The strongest takeaway is that these programs operate within a much more complex social and economic context,” she said. “Results often differed by age, sex, food security status, income, race and ethnicity, or program design.”
For families across the St. Louis region, those programs often play a critical role in ensuring children have consistent access to nutritious food, said Melissa Weissler, chief program officer at Operation Food Search.
“These programs and the food they provide are crucial to kids’ health,” Weissler said. “The meals a child receives at school are often the healthiest meals they consume, increasing their fruit, vegetable and whole grain intake.”
Many of the families served by the nonprofit face significant barriers to accessing healthy food, she said, including a lack of reliable transportation to grocery stores and limited household income to spend on fresh produce. In those circumstances, school meals and federal nutrition programs can make a measurable difference not only in diet quality but also in children’s well-being.
“A healthy diet influences academic performance and improves social-emotional health,” Weissler said.
For parents like Brittney Laden, a single mother of four who relies on SNAP benefits, the program is essential to keeping food on the table.
“It helps because the food is so expensive, and my kids don’t go hungry,” Laden said. “I can buy more food for my kids.”
She said SNAP has also made it possible to purchase healthier options that might otherwise be out of reach.
“The fact that I can now afford to buy my kids healthy food — I don’t understand why healthy food has to be so expensive,” she said.
While policymakers in some states are considering limiting certain foods that can be purchased with SNAP benefits, Moreland-Russell said the body of research reviewed does not support the idea that federal nutrition programs themselves are driving unhealthy weight gain among children.
“Our evidence argues for caution against framing SNAP as a cause of childhood obesity,” she said.
Laden said she understands some concerns about restricting sugary items but questioned broader limits on what families can buy.
“She agrees with lawmakers to a certain extent on sugary items,” Laden said. “But why should seafood be a restriction? It just makes it that much more difficult to buy. Just because someone is on SNAP doesn’t mean they shouldn’t enjoy so-called luxury food.”
Weissler said the policy debate should also take into account the financial realities families face when trying to feed their children.
“They need to understand that no one wants to ask for food. No one wants to struggle to feed their children,” she said. “The financial realities faced by the people we serve are overwhelming, and the investment we as a society make in food assistance has incredible returns.”
Programs that support nutrition during pregnancy, ensure children have enough to eat at school and help seniors access healthy food ultimately benefit communities and reduce long-term health costs, she said.
On the ground, those programs can also help families afford healthier foods. Through Operation Food Search’s MetroMarket — a mobile farmers market that brings fresh food directly to neighborhoods — thousands of families use SNAP benefits to purchase fruits and vegetables each year.
Weissler said the program recorded nearly 3,900 transactions using SNAP benefits last year. Many of the shoppers have extremely limited incomes; at least 23% report annual household earnings below $10,000, while more than 39% work full-time.
“These are people who struggle to get healthy food,” Weissler said. “Getting the nutritious food they need at reduced prices allows them to save money for other necessities like transportation and prescriptions.”
Moreland-Russell said the broader research suggests policymakers should focus less on program participation itself and more on the conditions that shape children’s diets and health.
“Our review points to the importance of looking beyond program participation alone and focusing on the broader conditions shaping children’s diets and health,” she said. “That includes household economic hardship, the affordability of healthy food, neighborhood food environments, and whether children have regular access to nutritious meals at home and at school.”