Grant: Operating Grant

This research aims to assess the influence of genetics on food intake and its contribution to the etiology of human obesity. The general objective is to use a twin-study design to investigate the quantitative genetic, shared, and unique environmental influences on dietary intake, and to estimate its contribution to the development of obesity. Data collected from a birth cohort of 675 twin pairs born between 1996-1998 will allow us to assess the extent to which different food intake and eating behaviours, measured from birth to 9 years of age, and usual dietary intake, measured at 9 years of age, account for the genetic and environmental (shared and unshared) influences on body weight trajectories and the development of obesity to the age of 15 years. This includes an investigation of common, correlated, and interacting genetic and environmental effects on dietary habits and on the development of obesity. This research is important because, in most cases, obesity does not come about as a result of markedly defective biology, but rather by maladaptive behaviours nurtured by an obesogenic environment. A susceptibility to obesity is partly determined by genetic factors, but an "obesity-promoting environment" is typically necessary for its phenotypic expression. Such a genetically mediated susceptibility to environmental exposure may result from gene-environment interactions, mediation, and/or confounders. There is a paucity of literature on gene-diet interactions in childhood obesity, and large twin-birth cohorts are essential for the development of such knowledge.