The role of the bacteria that reside in the human gut play in human health and disease is of increasing importance. Evidence gathered over recent decades' shows that certain bacteria can improve resistance to gut infections, reduce cholesterol levels, synthesise vitamins and improve the immune response. The potential to modulate the relative balance of these so-called 'beneficial' bacteria has been demonstrated through the use of certain fibre sources termed prebiotics. In addition there is interest to understand how snacks containing these fibre sources may affect levels of 'satisfaction' between meals. The current study will address these issues and lead to a greater understanding of the role that prebiotics may play in gut health and overall metabolism.