Dietary phosphorus (P) restriction is crucial to treat hyperphosphatemia and reduce cardiovascular disease risk and mortality in patients with chronic kidney disease (CKD) and the wider population. Various methods for dietary P restriction exist, but the bioavailability of P in food should also be considered when making appropriate food choices to maintain patients’ quality of life. Here, we propose the “Phosphatemic Index” (PI) as a novel tool for evaluating dietary P load based on P bioavailability; we also evaluated the effect of continuous intake of different PI foods in mixed meals on serum intact fibroblast growth factor 23 concentration.