DIAAS

DIAAS (Digestible Indispensable Amino Acid Score) is the modern protein quality measure adopted by the Food and Agriculture Organization in 2013, replacing the older PDCAAS rating. It scores how well a protein delivers essential amino acids in a form your body actually absorbs at the small intestine, where digestion really matters. A score of 1.0 means complete and fully digestible. Whey isolate scores 1.09, beef 1.11, soy isolate 0.92, pea isolate 0.79, and grains typically 0.4-0.6. The practical implication is that mixing rice with legumes pushes the score above 1.0, which is why combinations like rice and beans or rice protein with pea protein perform almost identically to whey for muscle protein synthesis. DIAAS matters most when total intake is borderline. If you eat 1.6+ g/kg from varied sources, the difference between a 0.85 and a 1.05 source becomes negligible. Use the protein calculator to set your daily target first, then choose sources based on cost, calories, and DIAAS together rather than fixating on one number.