Background:Eating disorders affect millions of people worldwide, but most never receive treatment. The majority of clinical research on eating disorders has focused on individuals recruited from treatment settings, which may not represent the broader population of people with eating disorders. This study compared the characteristics of individuals with eating disorders based on whether they self-reported accessing treatment or not, to identify potential differences and contribute to a better understanding of the diverse needs and experiences of individuals with eating disorders.Methods:The study population included 762 community-recruited individuals (85% female, M ± SD age = 30 ± 7 y) with bulimia nervosa and/or binge eating disorder (BN/BED) enrolled in the Binge-Eating Genetics Initiative (BEGIN) United States study arm. Participants completed self-report surveys on demographics, treatment history, past and current eating disorder symptoms, weight history, and current mental health and gastrointestinal comorbidity. Untreated participants (n= 291, 38%) were compared with treated participants (n= 471, 62%) who self-reported accessing BN/BED treatment at some point in their lives.Results:Untreated participants disproportionately self-identified as male and as a racial or ethnic minority compared with treated participants. Treated participants reported a more severe illness history, specifically, an earlier age at onset, more longstanding and frequent ED symptoms over their lifetime, and higher body dissatisfaction and comorbid mental health symptoms (i.e., depression, anxiety, ADHD) at the time of the study. Those who reported a history of inpatient or residential treatment displayed the most severe illness history, whereas those who reported outpatient treatment had a less severe illness history, and untreated individuals had the mildest illness history.Conclusions:Individuals from historically overlooked or marginalized populations were less likely to access treatment. Those who accessed treatment had more severe ED and comorbid symptoms, which may have motivated them to seek treatment. Clinic-based recruitment samples may not accurately represent all individuals with EDs, particularly those with milder symptoms and those with gender or racial/ethnic diversity. The results of this study indicate that community-based recruitment is crucial for improving the ability to apply research findings to broader populations and to reduce disparities in medical research.Trial Registration:ClinicalTrials.govNCT04162574(https://clinicaltrials.gov/ct2/show/NCT04162574)