Technical Abstract: Are there effects of morning nutrition on brain functions important for learning and performance in children? We used time-frequency analyses of EEG activity recorded while children solved simple math problems to study how brain processes were influenced by eating or skipping breakfast. Participants (8-11 yrs. old; IQ > 80) randomly assigned to treatment [eat (B) or skip (SB) breakfast (n = 41 each)], were grouped by age to adjust for learning experience [8.8 yrs. (B: n = 12; SB, n = 9), 9.7 yrs. (B, n = 15; SB, n = 18), 10.5 yrs. (B, n = 14; SB, n = 14). Problems (addition and subtraction) followed by 3 possible answers were presented on a monitor for 0.2 sec. Children were tested before and after treatment. Power at frontal and parietal sites for delta, theta, and alpha bands for problem presentation segments (correctly answered addition only) were analyzed (ANOVAs with post-hoc t-tests). In SB children theta and alpha power increased with extended fasting, and in older SB children delta power also increased (all p = .05). Power values for B children remained essentially stable between assessments. These findings reflect increased neural energy consumption and reduced neural efficiency in SB relative to B children, suggesting that SB children required greater mental effort than B children to do the math.