Genetic and Environmental Influences on Eating Behavior – a Study of Twins Reared Apart

Little information exists on the influence of genetic versus environmental factors on eating behavior. As part of the Tufts Twin Study, we assessed genetic (G), common environmental (C) and unique environmental (E) influences on eating behavior constructs and subscales by using the Eating Inventory (EI) in monozygotic twins reared apart (29 pairs) or together (49 pairs) (mean of all subjects±SD: age 36.2±13.6, BMI 24.5±4.5), and determined the extent to which G, C and E influences are shared by restraint (RES), disinhibition (DIS), and hunger (HUN) using model‐fitting analyses. The variance of most EI variables was primarily explained by E, which most strongly influenced external locus for HUN and strategic dieting behavior of RES (explaining 71% and 69% of variance, respectively). However, G had a significant influence on RES, internal locus for HUN, and emotional and situational susceptibility to DIS (with heritabilities of 52%, 50%, 55% and 38%, respectively). Multivariate analyses showed that DIS and HUN share a common influence, while RES appears to be a distinct construct. These results provide insight into the etiology of eating behavior by identifying specific constructs of eating behavior that are heritable and others that are primarily influenced by E. Funding: NIH grants R01 DK046124, 5T32 HL069772, MH‐65322, DA‐18673, and USDA grant 58‐1950‐4‐401.