The comparison of VLPD + KA (for 3 months) and Mediterranean-based diet or usual diet in moderate staged CKD patients (stages 3b–4; eGFR 15–45 mL/min/1.73 m2) revealed that the first diet was associated with a decrease in serum phosphorus and PTH as well as lowered FGF23 levels [91,102]. Here, FGF23 is linked to chronic kidney disease.