We used a randomized crossover design whereby 23 healthy women [ mean SD age : 22 2 y ; mean SD body mass index ( in kg/m ( 2 ) ) : 22.5 1.8 ] followed two 16-d fully controlled dietary interventions involving consumption of either a low-protein diet ( 0.6 g protein kg body weight ( -1 ) d ( -1 ) , ~ 7 % of energy derived from protein , approximately half the normal protein intake ) or a high-protein diet ( 2.2 g protein kg body weight ( -1 ) d ( -1 ) , ~ 25 % of energy , approximately twice the normal intake ) .