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Comment by cthalupa | Hacker News Reader

> More than a billion asians eat nutritious, cheap and calorie-balanced meals every day, unprocessed. [...] rice

This is one of those reasons that the term 'processed' food is stupid. White rice is a very processed food - what is the removal of the bran and germ but processing? And many other 'processed' foods undergo processing with the same sort of ramifications for health.

Legumes are also not complete proteins in the majority of cases - soy is a significant exception here. Soy has a PDCAAS of 1, the same as whey, but lentils range from .5 to .7, many beans are around .6, etc., and this can end up meaning your 200g of protein ends up being quite different in impact to many of your body's uses for protein than someone else's 200g of protein.

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PDCAAS is dumb when looking at multiple foods. E.g., beans and rice, when consumed together, are like, 0.99, depending on the ratio. That is, the sum is greater than the parts.

Adding rice might get you close to that for the amount of rice you eat, but 1 cup of beans will get you 16g of protein and 1 cup of rice will get you 4g of protein.

So a chunk of your protein intake would still be incomplete. It's not like the ratios are perfect so that a cup of each gets you 20g of PDCAAS 1.0 protein. Doing some quick napkin math looking at the AA makeup and protein digestibility of the two, it's like 14g equivalent of PDCAAS 1.0 protein.

~25% is a pretty significant gap if you're trying to hit optimal levels for things like muscle growth, etc.

From what you just wrote, it appears you misunderstood what I said. Just to be clear:

Red kidney beans (50g): PDCAAS = 0.88, Protein = 11.25g Basmati rice (50g): PDCAAS = 0.7, Protein = 4.5g

Red beans + rice (50g, 50g): PDCAAS = 1.0, Protein = 15.75g

Milk (500g..): PDCAAS = 1.0, Protein = 15.5g

So, from a protein perspective (according to PDCAAS), 500g of milk will give you the same amount of usable protein as the 100g rice and beans meal. There is nothing left on the table.

So, just eating kidney beans, PDCAAS would say that you aren't really getting the full benefit of the "protein on the label". But once you combine it with rice, you are getting the full benefit (according to PDCAAS).

You can't look at the digestibility of the two foods in isolation to make the calculations.

As long as you are eating a varied diet, PDCAAS is pretty pointless. If you have an eating disorder, or food scarcity issues, then it might become important.

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