Obesogenic behaviors during structured periods among children and adolescents with intellectual and developmental disabilities: a systematic review and meta-analysis.
Kiely K, Brazendale K, et al. • The international journal of behavioral nutrition and physical activity • 2026
Periods of greater structure were associated with more favorable physical activity and diet outcomes among children and adolescents with intellectual and developmental disabilities, while sleep and sedentary/screen time did not align with the Structured Days Hypothesis.
Key Findings
Results
Physical activity levels in children and adolescents with IDD aligned with the Structured Days Hypothesis, being more favorable during periods of greater structure.
Random-effects meta-analysis standardized mean difference (SMD) for physical activity = 0.27 (95% CI: 0.13–0.40), p < 0.001
23 studies contributed to the physical activity meta-analysis
A positive SMD indicates higher physical activity during more structured periods
Results were synthesized using both fixed- and random-effects meta-analyses and represented with forest plots
Results
Dietary behaviors in children and adolescents with IDD aligned with the Structured Days Hypothesis, though evidence was limited.
SMD for diet = 0.16 (95% CI: 0.03–0.29), p = 0.02
Only 1 dietary study was identified, making interpretation limited
Authors note that 'evidence for dietary behaviors was limited'
The positive SMD indicates more favorable diet outcomes during more structured periods
Results
Sleep outcomes in children and adolescents with IDD did not align with the Structured Days Hypothesis.
Random-effects SMD for sleep = -0.01 (95% CI: -0.16–0.14), p = 0.88
11 studies contributed to the sleep meta-analysis
The near-zero SMD and non-significant p-value indicate no meaningful difference in sleep across structured and less-structured periods
Results
Sedentary behavior and screen time in children and adolescents with IDD did not align with the Structured Days Hypothesis.
Random-effects SMD for sedentary and screen time = -0.01 (95% CI: -0.38–0.36), p = 0.95
12 studies contributed to the sedentary behavior meta-analysis
The wide confidence interval and non-significant result indicate high variability and no consistent pattern across structured versus less-structured periods
Methods
A total of 33 eligible studies were identified from a comprehensive literature search of 4,236 screened papers examining obesogenic behaviors across contexts with differing degrees of structure in youth with IDD.
4,236 papers were screened; 323 full-text articles were retrieved for further review
Final inclusion: physical activity = 23 studies, sedentary behaviors = 12 studies, sleep = 11 studies, diet = 1 study
Databases searched included PubMed, PsycINFO, Embase, and Web of Science through end of 2024
Methodological quality was evaluated using the NHLBI tool
Two reviewers independently completed screening and data extraction
Background
Children and adolescents with IDD are at greater risk for obesity and poor obesogenic behaviors compared to their typically developing counterparts.
This risk difference provides the rationale for applying the Structured Days Hypothesis (SDH) to the IDD population
The SDH proposes that obesogenic behaviors worsen during periods of reduced structure (e.g., weekends, summer vacation) in typically developing youth
Children and adolescents with IDD were identified as having 'unique factors that may alter how structure influences obesogenic behaviors'
Structure was operationally defined as 'pre-planned, segmented, adult supervised, out-of-home programs'
Discussion
The authors identified substantial gaps in the literature, including small study numbers and methodological heterogeneity, and called for future rigorous longitudinal research.
Only 1 study examined dietary behaviors, representing a major evidence gap
Methodological heterogeneity was noted as a limitation across included studies
Authors recommend 'rigorous, longitudinal designs' to better understand the relationship between structure and obesogenic behaviors in youth with IDD
The findings 'highlight substantial gaps in the literature' despite supporting the relevance of the SDH in this population
What This Means
This research suggests that the environment and schedule surrounding children and adolescents with intellectual and developmental disabilities (IDD) — such as autism, Down syndrome, or intellectual disability — may meaningfully affect how physically active they are and what they eat. The study analyzed 33 research papers to test whether the 'Structured Days Hypothesis' applies to this population. This hypothesis, previously studied in typically developing children, proposes that kids are more physically active and have healthier behaviors on structured days (like school days or organized program days) compared to unstructured days (like weekends or summer vacations). The meta-analysis found that during more structured periods, children and adolescents with IDD were indeed more physically active (a statistically significant finding across 23 studies) and had better dietary behaviors (though based on only one study). However, the amount of time spent sitting or on screens and sleep patterns did not differ meaningfully between structured and less-structured periods.
This research matters because children with IDD already face a higher risk of obesity and related health problems compared to their peers without disabilities. If structured environments — such as school programs, therapeutic settings, or organized activities — are linked to healthier physical activity and eating habits, this could inform how programs and schedules are designed for this population. The finding that screen time and sleep were not affected by structure in the same way suggests that additional or different strategies may be needed to address these behaviors specifically in youth with IDD.
However, the authors caution that the evidence base is still limited, particularly for diet and sleep, and that the studies reviewed varied considerably in their methods. This research suggests that more rigorous, long-term studies are needed to fully understand how structured environments shape the health behaviors of children and adolescents with IDD, and to develop effective interventions for this underserved population.
Kiely K, Brazendale K, Hill M, Burkart S, Beets M, Adams E, et al.. (2026). Obesogenic behaviors during structured periods among children and adolescents with intellectual and developmental disabilities: a systematic review and meta-analysis.. The international journal of behavioral nutrition and physical activity. https://doi.org/10.1186/s12966-026-01881-5