What is PDCAAS, and why does it matter?

PDCAAS — Protein Digestibility-Corrected Amino Acid Score — rates protein quality from 0 to 1 by combining a source's amino-acid profile with how well it digests. Whey, casein, egg, and soy score at or near the 1.0 ceiling; most single plant proteins land lower, which is the technical reason plant powders blend sources. It is the standard behind "high-quality protein" claims. We reference it factually to explain why sources differ — it is a measurement, not a marketing grade, and it says nothing about any health outcome. DIAAS is a newer, more precise version some brands publish.