The Effects of Breakfast and Breakfast Composition on Cognition in Children and Adolescents: A Systematic Review

45 studies in 43 articles; 34 acute single-breakfast studies (24 breakfast vs no breakfast, 15 breakfast type comparisons), 11 chronic school-breakfast-programme studies

Children and adolescents; mix of well-nourished and undernourished samples, high- and low-income countries. Very little adolescent data.

Systematic review of intervention studies only (not observational correlations), organised by cognitive domain and by breakfast manipulation. The dominant design is the acute laboratory paradigm - fast overnight, eat or don't eat, then perform bespoke cognitive tasks in the same morning. The authors themselves flag small samples, insensitive cognitive tests, unnaturalistic breakfast manipulations and testing environments, and a near-total lack of adolescent data.

Breakfast relative to fasting produces a SHORT-TERM (same-morning) domain-specific benefit - attention, executive function and memory are facilitated more reliably than other domains - and the effects are MORE APPARENT IN UNDERNOURISHED CHILDREN. Firm conclusions cannot be drawn about breakfast composition or about chronic breakfast interventions because studies are few and inconsistent. Nothing here supports a durable effect on achievement in well-fed children; the reliable finding is that a fasted child performs worse on lab tasks that morning.

Low for the acute within-subject experiments (each child is their own control). But the acute paradigm answers a different question than "does feeding children breakfast raise achievement".