The most recent statistics from the Department of Health in Ireland (2005) indicate that the leading causes of death are those in which nutrition can play a key preventative role. The proposed study will provide information on the metabolic stress from varying body weight overlaid by the additional metabolic stress of a test-meal challenge, in this case being delivered in the form of an oral glucose tolerance test (OGTT) and oral lipid tolerance test (OLTT), standard metabolic challenges in post-prandial research. Previous studies assessing metabolic risk factors associated with a disease have typically focused on information collected from individuals in a fasting state only. However, it is equally important to assess how the body responds when stressed. Employing an acute high fat or carbohydrate intake is sufficient to induce a mild stress in which time an individual's unique post-prandial response can be monitored. This study will combine traditional markers (dietary, anthropometric, lifestyle, clinical and physical activity) with nutrigenomics, a tool that attempts to describe the genome-wide influences of nutrition by examining the impact of diet on genes (genomics), mRNA (transcriptomics), proteins (proteomics) and metabolites (metabolomics).