As researchers have searched for ways to explain the childhood obesity epidemic in the U.S., many have posited that a child's race or ethnicity alone can put them at greater risk of becoming overweight or obese.

Kim Eagle, a professor of internal medicine and health management and policy at the University of Michigan, was skeptical of this thinking. His hunch was that poverty was a much more important part of the equation.

And he saw an opportunity to parse the connections between childhood obesity, poverty and race in Massachusetts, where public health officials have been collecting race, body mass index and other data on about 112,000 students from about 70 of the state's school districts. Eagle and colleagues decided to compare those data to students' eligibility for free school lunch programs, an indicator of poverty, to find out what predicts whether a child might become overweight or obese.

"At first glance it looked like childhood obesity was more common among African-Americans or Hispanics," Eagle says. When they accounted for poverty, though, the trend vanished. What his findings, which appeared in December in the journal Childhood Obesity, show is that "[obesity] is not about our race or ethnicity at all — it's about resources," he says.

It's far from the first study to reach this conclusion. A 2012 paper published in the American Heart Journal that also looked at kids in Massachusetts found that prevalence of obesity and overweight in children rose in communities with lower household income.

While not entirely surprising, this is an important insight for our understanding of attitudes about childhood obesity. "When you have particular groups with higher rates of a problem, people start to think that they're doing something wrong that's specific to them," says Marlene Schwartz, director of the Rudd Center for Food Policy and Obesity at the University of Connecticut. "This [finding] helps fight against that bias."

For Eagle and his colleagues, understanding that it's poverty, not race, that can help explain obesity rates is also useful for addressing the crisis. Viewed through the lens of genetics or culture, the issue can feel intractable, Eagle says, but reframing it as a matter of resources points toward tangible solutions. "This is something communities can wrap their arms around," he says. "It's not something a child is born with."

In 2004, Eagle founded , a curriculum-based program aimed at curbing obesity in middle schoolers. Kids learn about nutrition, but they also get healthier options at school: Eagle's team has taken on vending machines and cafeteria menus — nixing two-for-one hot dog days and Pop-Tarts for breakfast. They also work on sports programs and school gardens.

Eagle says students at first complained about salad carts and yogurt in the cafeteria, but over time, they've turned out to be hugely popular. "It's not that students want to eat unhealthfully," he says. "A lot of times [unhealthy food is] all they have."

The program is now at more than 50 middle schools in Michigan. Eagle says while most kids of all income levels benefit within three months, he sees the most dramatic improvements in low-income students. And, he says, being vulnerable doesn't mean you're destined to be overweight and in poor health — if you intervene in communities with few resources, health outcomes can improve.

Copyright 2021 NPR. To see more, visit https://www.npr.org.