Submitted to: Open Nutrition Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2012
Publication Date: 3/1/2012
Citation: Elder, S.J., Neale, M.C., Fuss, P.J., Lichtenstein, A.H., Greenberg, A.S., Mccrory, M.A., Bouchard, T.J., Saltzman, E., Susan, R.B. 2012. Genetic and environmental influences on eating behavior - a study of twin pairs reared apart or reared together. Open Nutrition Journal. 6: 59-70. Interpretive Summary: Eating behavior is known to play an important role in energy regulation and the eating behavior construct Disinhibition is correlated with current body mass index (BMI), prior weight gain over 20 years and weight regain following weight loss. However, the extent to which different eating behaviors are influenced by genes versus environmental factors remains uncertain. The objectives of this study were to quantify the genetic, common environmental and unique environmental influences on eating behavior constructs and subscales assessed by the Three Factor Eating Questionnaire, and to determine the extent to which genetic and environmental influences are shared by restraint, disinhibition, and hunger. Data was collected as part of the Tufts Twin Study, an investigation of adult monozygotic twins reared apart (MZA) or together (MZT). MZA twin pairs constitute a particularly valuable group for assessing trait heritability because although they are extremely rare they provide substantial statistical power to estimate heritability compared to studies using other types of populations. Results suggest a relatively modest influence of genes and a strong influence of unique environmental factors on eating behaviors. Although studies of this kind do not directly address whether the heritability of eating behaviors reflects the extent to which they can be changed with behavioral weight control or other therapies, our results suggest that environmental factors generally play a substantial role in individual differences in eating behaviors.
Technical Abstract: This study examined the relative influence of genetic versus environmental factors on specific aspects of eating behavior. Adult monozygotic twins (22 pairs and 3 singleton reared apart, 38 pairs and 9 singleton reared together, age 18-76 years, BMI 17-43 kg/m2) completed the Three Factor Eating Questionnaire. Genetic and environmental variance components were determined for the three eating behavior constructs and their subscales using model-fitting univariate and multivariate analyses. Unique environmental factors had a substantial influence on all eating behavior variables (explaining 45-71% of variance), and most strongly influenced external locus for hunger and strategic dieting behavior of restraint (explaining 71% and 69% of variance, respectively). Genetic factors had a statistically significant influence on only 4 variables: restraint, emotional susceptibility to disinhibition, situational susceptibility to disinhibition, and internal locus for hunger (heritabilities were 52%, 55%, 38% and 50%, respectively). Common environmental factors did not statistically significantly influence any variable assessed in this study. In addition, multivariate analyses showed that disinhibition and hunger share a common influence, while restraint appears to be a distinct construct. These findings suggest that the majority of variation in eating behavior variables is associated with unique environmental factors, and highlights the importance of the environment in facilitating specific eating behaviors that may promote excess weight gain.