FGF23 and chronic kidney disease: In a short crossover study in CKD patients (1 week on very low-protein diet 0.3 g/kg/d supplemented with ketoanalogues; 1 week on low-protein diet 0.6 g/kg/d), Di Iorio et al. (175) have demonstrated a ~34% decrease in FGF-23 following the VLPD + ketoanalogues.