The Cognitive Functions of Youth With Obesity: A Meta-Analysis.

In 30 seconds

This PRISMA-guided meta-analysis pooled 22 studies comparing youth under 18 with obesity and normal-weight peers, using random-effects models to assess seven cognitive domains. Obesity was associated with poorer performance in six domains: inhibition (Hedges’ g = -0.193), cognitive flexibility (g = -0.499), working memory (g = -0.652), verbal fluency (g = -0.420), attention (g = -0.526), and IQ (g = -0.288); planning could not be estimated. Developmental subgroup differences were not significant. A higher female proportion at the study level was associated with larger working-memory deficits, while age did not moderate results.

Key findings

• Compared with normal-weight peers, youth with obesity had lower working-memory performance (Hedges’ g = -0.652) and attention performance (g = -0.526).
• Associations were also reported for cognitive flexibility (g = -0.499), verbal fluency (g = -0.420), inhibition (g = -0.193), and IQ (g = -0.288).
• School-age and adolescent subgroup differences were non-significant across domains (p ≥ 0.26); age did not moderate any domain.
• A higher female proportion in study samples was associated with larger working-memory deficits (p = 0.002), a study-level rather than individual-level finding.

Why it matters

The findings indicate that obesity in youth is associated with differences across several cognitive domains, not solely executive functions. This may be relevant when interpreting cognitive performance in research and clinical assessment. However, the results describe group-level associations and do not establish that obesity causes cognitive differences or predict an individual young person’s functioning.

What to keep in mind

Substantial heterogeneity, predominantly observational study designs, inconsistent BMI criteria, and limited ADHD-stratified data constrain causal inference. Planning could not be estimated, and developmental subgroup differences were non-significant.