School Nutrition: Food for Thought
The latest such study, published in the journal Child Development, followed 6,250 children from kindergarten through fifth grade and found that those who were obese throughout that period scored lower on math tests than non-obese children.
What's more, this pattern held even after the researchers took into account extenuating factors that can influence both body size and test scores, such as family income, race, the mother's education level and job status, and both parents' expectations for the child's performance in school.
The study took another step in this direction by looking at the children's social skills and any outward signs of anxiety, sadness, loneliness, or low self-esteem. Obese students generally displayed more emotional difficulties than their non-obese counterparts, and obese girls -- but not boys -- also displayed poorer social skills.
Social and emotional problems may not be the whole story, however. It's also possible that some of the well-documented health problems associated with childhood obesity -- such as asthma, diabetes, and sleep disorders -- may interfere with schoolwork or cause kids to miss class time.
Even more insidiously, excess weight or physical inactivity might sap a child's brainpower at the cellular level, by causing inflammation and other harmful biological processes, says Robert Siegel, M.D., director of the Center for Better Health and Nutrition, a pediatric obesity clinic at Cincinnati Children's Hospital.
"Obesity affects virtually every organ system in the body, including the brain," Siegel says. "It's an inflammatory state, and that may have effects on the developing mind."
Nationwide, an estimated 32% of American kids ages 2 to 19 are overweight, including 17% who are obese, according to the Centers for Disease Control.Promote Proper Nutrition.