Protein differences

I have read on here several times that collagen protein isn't good for WLS surg pts. Why is that? Can any one explain?

Easiest way I've found to break it down.

Whey vs Casein vs Collagen

asmbs nutritional guidelines *Ctrl F and type in Whey*

*Edited to add link

This is the best explanation I've read:

Not all protein has the same value to your body. The amino acid profile
is the reason for this. Proteins are made of amino acids. There are 20
different ones in the human body. Of the twenty, 9 of them must be
consumed to meet your daily needs. These 9 amino acids are called
Essential (EAA) or Indispensable.

The 9 EAAs are needed in certain proportions. A protein scoring system
called Protein Digestibility Corrected Amino Acid Scoring (or PDCAAS)
was developed to show which products contain all the EAA and in the
correct proportions. It is supported by the FDA, the World Health
Organization, and perhaps most importantly, the Institute of Medicine at
the National Academy of Sciences. The highest possible score is 100.

-- Collagen Protein gets a 0 (the lowest possible score)
-- Whey Protein Isolate gets 100 (the highest possible score)

Some proteins such as COLLAGEN or HYDROLYZED COLLAGEN protein are
missing one of the EAAs entirely. So the PDCAAS for collagen is zero.
Collagen is often the main ingredient in protein supplements that come
in a liquid form, and they usually have lower PDCAAS scores.

So it's not just a poor choice of protein for WLS patients, it's a bad choice of protein for everyone.  

The dialysis center I work at gives pts with low albumin levels an oz of liquicel every treatment...just curious. TY 

I forget the brand, but I have seen one brand of protein shot that was whey instead of collagen. But no one that has tried any type of shot found them palatable. They are all truly horrid.

I've seen Yes Whey, which says they are 100% whey but they seem to be discontinued.