To add a bit to the title:

If I eat 5 grams of protein from white rice, and 7 grams of protein from beans, have I eaten 12 grams of complete protein? Have I eaten 5 grams? Something else?


1 Answer 1


A "complete protein" is not actually a protein, but rather the full set of essential amino acids in the right proportion. You can use that proportion to determine how many "sets" of complete protein you have and which amino acids you got that were "extra". I'm of the opinion that this exact breakdown isn't useful, but you can use the profile of a complete protein to calculate the total amount of complete protein.

It's easiest to use ratios. For example, if your meal contained 10 mg of Tryptophan, divide that by 7 mg/g from the chart to get 1.42. If it had 54 mg of Threonine, divide that by 27 mg/g to get 2.00. Do this for all of the amino acids, then select the lowest ratio. Let's assume that you continued through the chart and all the other ratios were higher than 1.42, so 1.42 is the minimum. You therefore got 1.42 grams of complete protein. You also got (2.00 - 1.42) * 27 mg of "extra" Threonine, as well as extra of the other amino acids besides Tryptophan.

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