New research suggests that previous theories about why some poor children are obese (e.g., eating junk food instead of nutritious food or not eating when cash is short, prompting a yo-yo metabolic cycle) aren’t necessarily sound. By challenging long-held theories, the researchers hope to encourage more research into the issue; some studies show that nearly a third of American children ages 10 to 17 are overweight or obese, and that nearly 40 percent of those kids are from low-income households. For the study, the researchers analyzed 1999 data about 1,031 children living in low-income households in Boston, Chicago, and San Antonio. They assessed whether the children had enough food for a healthy, active lifestyle (called “food security” by researchers). They looked at the individual child, instead of their entire household as previous studies had done. The researchers asked the children’s mothers whether she had reduced the size of a meal due to lack of food or money, if her child skipped a meal because food wasn’t available, and if her child went hungry because she couldn’t afford more food. Researchers found that children who didn’t get enough food weren’t more likely to be overweight, even though the two factors often coexisted in the low-income population they studied.