While searching for references on the dietary requirements of laboratory animals, specifically Rattus norvegicus (I have several pet rats), I came across the catalogue of the National Academies Press, a joint operation of the U.S. national academies of sciences, engineering, and medicine. (Their publications can be dowloaded for free, it seems, but the .pdf cannot be legally shared, only an on-line reference.)
Their reference on dietary intake in human beings may be of interest to members of these forums:
