Very interesting - I'm not sure I understand the difference here if this is not in reference to something like DIAAS - which is the scientifically agreed upon method for measuring amino acid absorption from food. Could you maybe point me toward some scientific literature discussing this?

Alternatively can you point out where in the below logic chain I've gone wrong:

- food contains calories: made up (in general) of carbs, fat, protein

- the labels on food do not reflect the calories in food due to digestibility: this is due to the well known "Atwater Factors" i.e. we do not absorb all the calories (of any kind - protein, fat or carbs) that we ingest - but this is accounted for in the food labels so we don't need to care about this necessarily if we go on label quantities

- when it comes to the protein that we ingest, there is a difference between using it as energy (conversion to fat then ATP) and using it to repair muscle

- current scientific literature points to the fact that there is not much difference in the availability of this protein for muscle repair once you hit your threshold of lysine consumption - which if you are not starving, you almost always do

I'm very curious to understand what's at odds here. I'm guessing it's the last point but that is discussed in the video I recommended above where the point remains. Eating a standard "Eatwell diet" provides enough lysine that the source of amino acids doesn't matter - because it has the same bioavailability once you have enough lucine.