Abstract
Dietary protein provides amino-acids to maintain the proteome's content, structures and function of the organism and to provide for growth and special needs. Individual and population allowances for dietary protein for adults derive from nitrogen balance studies. These are difficult to design, execute and interpret and current allowances are controversial. Because of adaptation of the metabolic demand for amino-acids to habitual protein intakes, the true minimum protein intake which will maintain a healthy body composition may not be captured in most short term (two week) balance studies and the efficiency of utilization of dietary protein is markedly underestimated. The implication of these difficulties for currently defined protein allowances for children, adults and pregnancy is critically evaluated.