system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Pork rinds are incomplete protein and are labeled "not a good source of protein" but beans are also an incomplete protein and do not have this same label. Why?
gpt
Because it's not just a question of protien, but of the types of protien and the regulation. In the USA,  the Food and Drug Administration requires that food for people aged 4 and over that has, "a protein quality value that is a protein digestibility-corrected amino acid score of less than 20" must have the label, "not a good source of protien." What this means is that the foodstuff in question must have a certain number of absorbable proteins or it must have the label.  

How does this relate to beans and pork rinds? Pork rinds are fried pig skins, therefore they're rich in collagen, the protien that gives human skin structure too. Unfortunately, that's about the only protien it provides, worst still humans don't digest nor absorb that protien very efficiently. On the flip side, beans have a wider variety of more easily digested and absorbed proteins so it is not affected by the regulation.

Edit: it's 4 and over, not just 4.