Protein PDCAAS vs amino acid profile

Nutrition Q&A [Moderated]
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Mike Israetel just released a video where he explained that protein sources with a low PDCAAS score can’t be effectively digested by the body.

However, if a person is vegan, they’ll get most of the protein from sources such as lentils, beans, and other legumes, unless they eat tofu or drink protein powder all day. If such a person tracks their food intake in a tool like Cronometer, the tool will show that even if they get protein from “mediocre” sources like peanut butter, and legumes, they’ll get all the amino acids required to absorb the protein at the end of the day. Of course, unlike when eating meat, they won’t be getting all the amino acids at each meal, but the acids from all meals will add up at the end of the day.

Mike also said that 75% of the daily protein intake should come from sources with high PDCAAS score or else muscle protein synthesis will likely be impaired.

My question is, given that even “low quality” protein sources can help a person reach all the amino acids required for muscle protein synthesis, how relevant is it to consider eating mostly foods that rank high in PDCAAS? For example, suppose a person eats 1.6g/kg of protein per day with most of the protein coming from low quality sources but Cronometer shows that all amino acids reached their targets at the end of the day, would muscle protein synthesis be impaired because the person didn’t stick with high PDCAAS foods?

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I do not think that PDCAAS is relevant at all in the context of someone hitting ~ 1.6g/kg/day of protein. I would not agree that people would see better results by getting the majority of their protein from sources with a high PDCAAS score. I also think there are issues with the PDCAAS score in and of itself.

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Thanks for the quick response Jordan. I’ve been reading about that and many people, especially in the plant based diet space argue that one can still get jacked eating mostly legumes. There are also many others who argue that meat sources are undeniably better than protein from plants. With no evidence provided, of course.

Are there any good studies about that, and could you recommend any?

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Yes, there are a number of them. We cite some of them in our Protein Guidelines.

I do not think people who argue that individuals must eat meat to get big and strong are familiar with the evidence.

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