Understanding why digital device use translates into excess body weight in children requires moving beyond simple sedentary behavior arguments — and this review does exactly that, mapping four distinct biological and behavioral pathways that may collectively tip young people toward positive energy balance.
Drawing on literature published between 2015 and 2025 across MEDLINE, Web of Science, and Scopus databases, the analysis identifies reduced physical activity displacement as only one of several mechanisms. Circadian rhythm disruption from screen-emitted light — particularly blue-spectrum wavelengths — appears to suppress melatonin and fragment sleep architecture, with downstream effects on appetite-regulating hormones such as leptin and ghrelin. Elevated stress biomarkers associated with high-intensity media content or social media use represent a third pathway, given cortisol's role in promoting visceral fat accumulation. Adverse mental health outcomes, including anxiety and depressive symptoms, complete the picture by independently influencing dietary patterns and motivation for physical activity. The authors emphasize that these pathways interact and mutually reinforce one another rather than operating in isolation.
This narrative review consolidates a decade of pediatric research at a moment when average daily screen exposure in children continues to climb well past existing guidelines. Mechanistically, the circadian and stress-cortisol pathways are the most underappreciated by parents and clinicians, who typically focus on snacking during viewing or reduced movement. The four-pathway framework presented here is conceptually useful but inherits the limitations of narrative methodology: publication bias toward positive associations is plausible, causality cannot be established from largely observational constituent studies, and effect sizes across individual pathways remain poorly quantified. Screen type — passive television, social media scrolling, or active gaming — likely produces meaningfully different physiological profiles, a nuance this review does not fully resolve. Still, for a health-conscious readership, the implication is clear: the metabolic risk of excessive screen time in children is more biologically complex, and therefore more difficult to fully mitigate, than simply swapping screen minutes for outdoor play.
