Increased fiber intake has been linked with lower risk of overweight and obesity in adults, but data are sparse for children. To address this issue, NHANES 2003-2006 data was used to evaluate (1) the food sources of fiber in children, (2) the dietary fiber density levels and risk of being classified as overweight/obese, and (3) the association between fiber intake level and impaired glucose metabolism in children. Analyses were restricted to the subsample of children with biological plausible diet reports (N = 4,667) and stratified by 2-11 year olds (n = 2072) and 12-18 year olds (n = 2595). Results showed that the food sources are predominantly foods that are low in dietary fiber, but are consumed at high levels. In 2-18 year old plausible reporters, the risk for overweight/obesity decreased by 17% from children in the medium tertile of fiber density intake compared to the lowest tertile (OR = 0.83, P value = 0.043) and by 21% between the highest compared to the lowest tertile (OR = 0.79, P value = 0.031). There was a protective effect of being in the medium tertile of dietary fiber density (OR = 0.68, P value <0.001) on impaired glucose metabolism. These results indicate a beneficial effect of higher fiber density in children's diets.