Free Protein Quality Calculator
Score any meal for protein quality using PDCAAS and DIAAS, and find complementary protein pairings for a complete amino acid profile. Based on the FAO/WHO 2013 reference pattern.
Ingredients
References & sources
- [1]FAO. Dietary protein quality evaluation in human nutrition: Report of an FAO Expert Consultation. FAO Food and Nutrition Paper 92. Rome, 2013.
- [2]WHO/FAO/UNU. Protein and amino acid requirements in human nutrition: Report of a Joint WHO/FAO/UNU Expert Consultation. WHO Technical Report Series 935. Geneva, 2007.
- [3]Rutherfurd SM, Fanning AC, Miller BJ, Moughan PJ. Protein digestibility-corrected amino acid scores and digestible indispensable amino acid scores differentially describe protein quality in growing male rats. J Nutr. 2015;145(2):372-379.
- [4]Herreman L, Nommensen P, Pennings B, Laus MC. Comprehensive overview of the quality of plant- and animal-sourced proteins based on the digestible indispensable amino acid score. Food Sci Nutr. 2020;8(10):5379-5391.
- [5]Phillips SM. The impact of protein quality on the promotion of resistance exercise-induced changes in muscle mass. Nutr Metab (Lond). 2016;13:64.
- [6]US Department of Agriculture, Agricultural Research Service. FoodData Central (USDA).
Medical disclaimer
This tool uses published PDCAAS and DIAAS values from peer-reviewed literature and FAO datasets. Values can vary between studies, processing methods, and measurement protocols. It is a directional educational tool \u2014 not validated for clinical nutrition support, bariatric practice, research submissions, or regulatory/label claims. For those use cases, consult a registered dietitian and use fully-traceable analytical software or laboratory testing.
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자주 묻는 질문
What is the difference between PDCAAS and DIAAS?
PDCAAS (Protein Digestibility-Corrected Amino Acid Score) is the FAO/WHO standard for labelling since 1993. DIAAS (Digestible Indispensable Amino Acid Score), introduced in 2013, measures digestibility at the end of the small intestine rather than the faeces and is not truncated at 1.0. DIAAS is considered more accurate but data coverage is still growing.
Do vegans need to worry about protein quality?
Meeting total protein needs is the first priority. Beyond that, variety matters: combining legumes with grains (lysine-limited + sulphur-limited) over the day produces a complete amino acid profile. You do not need to combine them in a single meal — modern consensus is that daily patterns are what count.
Which plant foods have the highest protein quality?
Soy protein isolate (DIAAS ~0.90), pea protein isolate (~0.73), and quinoa (~0.73) rank highest among plant sources. Mycoprotein and some novel proteins score even higher in the latest research. Most other single-source plant proteins are limited in either lysine (grains, nuts) or sulphur amino acids (legumes).
Is the "incomplete protein" myth real?
No single meal combining is required, and most plant foods actually contain all essential amino acids — just in lower proportions. The 1970s concept of complementary protein combining at every meal is outdated. Eating varied plant proteins across the day is sufficient for adults meeting their total protein target.
Can this calculator be used for clinical or research work?
It is a directional tool built on published PDCAAS/DIAAS data and the FAO 2013 adult scoring pattern. For clinical nutrition support, bariatric practice, research, or label claims, use validated software with fully traceable amino acid datasets. This tool is for education and client counselling.