The idea that anything containing amino acids can have 0 kcal seems a little odd to me, but I realize a lot of companies seem to advertise any product with FFAAs as 0 kcal.
How does that even make sense from a physiological standpoint? If it were true, any sort of enzymatically pre-digested protein (think hydrolized) should be completely kcal free. To take it one step further, protein should have zero kcal because it's just FFAAs chained together. Always wondered whether I'm missing something here.