In human and pet nutrition, few issues have captured attention in the way that dietary fiber and functional ingredients have in recent years. Dietary fibers are non-digestible carbohydrates and lignins that are intrinsic and intact in plants, while added fibers consist of isolated, non-digestible carbohydrates which have beneficial physiological effects in human and pet nutrition. Total fiber is then a sum of dietary fibers and added fibers, which together or alone will be referred as dietary fiber (DF).