Dietary restraint is a prospective risk factor for the development of binge eating and bulimia nervosa. Although many women engage in dietary restraint, relatively few develop binge eating. Dietary restraint may only increase susceptibility for binge eating in individuals who are at genetic risk. Specifically, dietary restraint may be a behavioral "exposure" factor that activates genetic predispositions for binge eating. We investigated this possibility in 1,678 young adolescent and adult same-sex female twins from the Minnesota Twin Family Study and the Michigan State University Twin Registry. Twin moderation models were used to examine whether levels of dietary restraint moderate genetic and environmental influences on binge eating. Results indicated that genetic and non-shared environmental factors for binge eating increased at higher levels of dietary restraint. Importantly, these effects were present after controlling for age, body mass index, and genetic and environmental overlap among dietary restraint and binge eating. Results suggest that dietary restraint may be most important for individuals at genetic risk for binge eating, and the combination of these factors could enhance individual differences in risk for binge eating.
Keywords binge eating; dietary restraint; gene-environment interactions; twinsEating disorders are debilitating conditions that affect 0.5-3% of adolescent and adult women (American Psychiatric Association (APA), 2000). One symptom of eating disorders that cuts across virtually all eating disorder diagnostic categories is binge eating. Binge eating is defined as consuming an amount of food over a discrete period larger than what most individuals would eat and experiencing a sense of loss of control while bingeing (APA, 2000). Importantly, regular binge eating is present in adolescent and adult community populations (prevalence rates: 1.8-5%) (Hay, 2003;Hudson, Hiripi, Pope, & Kessler, 2007;Jones, Bennett, Olmsted, Lawson, & Rodin, 2001) and is associated with reduced quality of life and greater psychopathology (Hay, 2003). Thus, it is critical to understand the etiology of binge eating.Corresponding Author: Kelly L. Klump, Ph.D., Department of Psychology, Michigan State University, 107B Psychology Building, East Lansing, MI 48824-1116, PH: 517-432-9861, FAX: 517-432-2476.edu. Publisher's Disclaimer: The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/pubs/journals/abn. Extant cross-sectional and longitudinal data suggest that dietary restraint (i.e., the intent and/ or attempt to restrict caloric intake) increases r...