Autistic adult outcomes on weight and body mass index: a large-scale online study

PURPOSE: There has been a wealth of work on the weight outcomes of autistic children and young people, generally finding that they are more likely to be overweight or obese than their non-autistic counterparts. There has not been the same focussed study of the weight outcomes of autistic adults, however. This study, therefore, sought to examine the relationship between weight outcome and being autistic in adults. METHODS: Data were collected as part of an online study looking at eating, autism, and relationships. 665 people gave demographic and mental health information, and group differences and robust regressions were conducted. RESULTS: Autistic adults were more likely to be in non-healthy weight categories than their non-autistic counterparts, i.e., more likely to be underweight, overweight, or obese. There were no interactions between autism status and mental health impacting BMI, although both anxiety and depression predicted higher BMI in the sample overall. CONCLUSIONS: We conclude that while some weight patterns from childhood and adolescence continue into adulthood for autistic individuals, this is not necessarily a straightforward picture, and would benefit from further in-depth and qualitative study to understand the processes at play. The lack of interactions between mental health and autism, however, should provide professionals with confidence in supporting healthy weight management among autistic people. LEVEL OF EVIDENCE: Level III, cohort study.