Applied nutritional investigation Inﬂuence of heredity on dietary restraint, disinhibition, and perceived hunger in humans John M. de Castro, Ph.D.*, Lisa R. R. Lilenfeld, Ph.D. Departments of Psychology, The University of Texas at El Paso, El Paso, Texas, and Georgia State University, Atlanta, Georgia, USA Manuscript received July 28, 2003; accepted July 24, 2004. Abstract Objective: Dietary restraint, disinhibition, and perceived hunger have been shown to affect food intake and body weight and are thought to be risk factors for eating disorders, but little is known about their origins. We investigated the inﬂuence of heredity, shared (familial) environment, and individual environment on dietary restraint disinhibition, perceived hunger and their relation to body size and food intake. Methods: Scores on the Three Factor Eating Questionnaire and the Restraint Scale in addition to height, weight, body mass index, and 7-d diary reported nutrient intakes were obtained from 39 identical, 60 fraternal same-sex, and 50 fraternal opposite-sex adult twin pairs who were living independently. Linear structural modeling was applied to investigate the nature and degree of genetic and environmental inﬂuences. Results: Analysis showed signiﬁcant genetic and individual environmental, but not shared (famil- ial) environmental, inﬂuences on cognitive restraint, perceived hunger, and Restraint Scale scores, with genes accounting for 44%, 24%, and 58% of the variance, respectively. In contrast, disinhi- bition was found to be signiﬁcantly inﬂuenced by the shared (familial) environment, accounting for 40% of the variance. Further analysis showed that cognitive restraint and perceived hunger herita- bilities could not be accounted for by signiﬁcant heritabilities of body weight, height, or body mass index. In contrast, the heritability of Restraint Scale scores was found to be related to body size. Cognitive restraint was negatively correlated with nutrient intake, and differences in cognitive restraint were found to be related to differences in the body sizes of identical twin pairs. Conclusions: Dietary restraint appears to be another component in a package of genetically determined physiologic, sociocultural, and psychological processes that regulate energy balance, whereas dietary disinhibition may be the intermediary between upbringing and the development of overweight and/or eating disorders. © 2005 Elsevier Inc. All rights reserved. Keywords: Eating; Heredity; Twins; Restraint; Disinhibition; Hunger Introduction Heredity appears to inﬂuence body size [1– 8] and food and ﬂuid intakes of humans [9 –11]. Interestingly, inheri- tance appears to affect daily intake in a fashion that is independent of body size [9]. In addition, heredity appears to inﬂuence the microstructure of intake independent of the level of overall daily intake, including the number, timing, and composition of meals and drinks [9,10,12,13]. How- ever, the effect of heredity on intake is even subtler than its inﬂuence on the fundamental components of food intake control. Heredity also appears to indirectly affect intake by inﬂuencing environmental, social, and psychological fac- tors, which in turn affect intake [14 –18]. Heredity appears to inﬂuence the time of day that people tend to eat and how large an effect the selection of that time will have on their intake [17]. Heredity also appears to inﬂuence the degree of stomach ﬁlling that an individual tends to have before and after a meal and the degree of restraint exerted by stomach ﬁlling on the amount eaten during meals [15]. Genes have This study was supported in part by grant R01-DK39881 from the National Institute of Diabetes and Digestive and Kidney Diseases and by a Georgia State University Research Enhancement Program grant. * Corresponding author. Tel.: +915-747-6558; Fax: +915-747-6553. E-mail address: jdecastr@utep.edu (J.M. de Castro). Nutrition 21 (2005) 446 – 455 www.elsevier.com/locate/nut 0899-9007/05/$ – see front matter © 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.nut.2004.07.010