Hi Steven,

I assume you’re getting at the fact that proteins from animal sources tend to be highly bioavailable — fully absorbed — while those from plant-based sources vary greatly.

On the high end, soy rocks at 95–98%. On the low end, some grains and legumes (beans, lentils) are as low as 72%. This suggests that we absorb 7.2 grams for every 10 grams of whole bean protein.

I did not explicitly adjust numbers for each protein based on absorption estimates, in part because such data are only available for a handful of the proteins in my dataset, but also because these estimates are highly flawed. They are based on experiments performed in rats, in unrealistic conditions (single foods). For example:

Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats


At the same time, I think it makes sense for those on a plant-based diet to consider a small protein “boost” to account for lower absorption. This is why I personally aim for 1 g/kg protein per day rather than the RDA of 0.8 g/kg. All of my graphs are based on this assumption of 60 g protein daily (1g/kg for me).

Also, to be clear, the ratios of essential amino acids in a given protein are what they are — based on the plant’s genetic code. We don’t know enough to precisely adjust the bioavailability of each amino acid in each food.

I hope this answers your question!



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Scientist (PhD Genetics @Stanford) * Mother * Passionate about science-based healthy choices * Lifelong learner * Founder: Fueled by Science

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