Body weight in autism spectrum disorder: A systematic review and meta-analysis

Evidence on the relationship of autism spectrum disorder (ASD) to overweight/obesity and underweight is mixed. Moreover, it is unclear how this relationship changes with age.

We carried out a systematic review (SR) with meta-analysis on the association between ASD and obesity, overweight and underweight across the life span. The study was based on a pre-registered protocol (PROSPERO: CRD42024524084). Web of Science and PubMed were searched until the 8th of April 2025. We assessed the quality of the included studies with the Newcastle-Ottawa scales (NOS).

A total of 9075 records were screened, of which 64 studies reporting data on obesity, overweight and/or underweight on ASD and controls general participants were included in the SR and 62 meta-analyzed. We found a significant association between ASD and obesity (OR = 1.93; CI = 1.70-2.19; i ² = 99.02%), ASD and overweight (OR = 1.73; CI = 1.43-2.09; i ² = 95.44%) but, at the group level, not ASD and underweight (OR = 1.22; CI = 0.91-1.64; i ² = 78.37%). There was a statistically significant association between ASD and underweight in adolescents (OR = 1.32; CI = 1.12-1.56) and adults (OR = 2.14; CI = 1.5-3.04). The score on the Newcastle-Ottawa Scale showed that, overall, studies had a medium risk of bias (median = 6, range 1-10).

Individuals with ASD have an elevated risk of being obese or overweight, and, in adolescents and adults, of underweight. Our study may contribute to the development and implementation of targeted prevention and intervention strategies, aimed at enhancing the physical well-being of individuals with ASD and their caregivers, ultimately improving their quality of life.