Plant Protein Combining Calculator
Score any plant-based meal against the WHO reference pattern — and see which amino acid is limiting.
Build your meal
- Lysine131%
- Methionine + Cysteine129%
- Tryptophan181%
- Threonine174%
How this is calculated
For each food you add, we sum grams of essential amino acids (using USDA-derived per-100 g values), divide by total protein, and compare against the WHO adult reference pattern (mg amino acid per g protein): lysine 45, methionine+cysteine 22, tryptophan 6, threonine 23.
The lowest score is the "limiting" amino acid — the one that caps how much of the protein your body can use for building new tissue. A daily rotation of legumes, grains, and a nut or seed reliably hits 100% across the board without per-meal math.
Frequently asked
Do I really need to combine proteins?+
Not per meal. The 1970s 'protein combining' idea was retired decades ago — your body pools amino acids from everything eaten across a day. But if a single meal is your main protein source (a burrito, a curry), pairing a legume with a grain still gives a more complete profile.
Which combinations work best?+
Legumes are low in methionine but high in lysine; grains and nuts are the opposite. Classic pairs: rice + beans, hummus + pita, peanut butter + whole-wheat toast, lentil + rice dal, tempeh + quinoa.
How does this calculator score my meal?+
It sums the amino acids from the foods you add, divides by total protein, and compares each essential amino acid to the WHO adult requirement. A score of 100% means all four scored amino acids meet or exceed the reference — a 'complete' meal.
Related tools
References
- World Health Organization / FAO / UNU. Protein and Amino Acid Requirements in Human Nutrition. WHO Technical Report Series 935, 2007.
- Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr. 1994;59(5):1203S–1212S.
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central. USDA, 2024.
Educational estimates only, not medical advice. Individual needs vary — consult a physician or registered dietitian.