Briefly noted: A Muntaner-Mas et al. J Pediatr 2018; 198: 90-7. This cross-sectional study with 250 Spanish children (10-12 year olds) examined obesity measures, physical fitness measures and academic performance. Key finding: “Children considered fit had better academic performance than their unfit peers…the association between body mass index and GPA was mediated by cardiorespiratory fitness and speed-agility.” The design of this study precludes establishing this association as a causal relationship.