Amino acids are wasted ( not used to build protein) whenever there is :

Amino acids are wasted whenever there is:
 NOT ENOUGH ENERGY FROM CARBOHYDRATE AND FAT
LOW QUALITY PROTEINS
 EXCESSIVE PROTEINS 
When these conditions occur in the body, the amino acids are wasted in the sense that they will be degraded and destroy; the body will not use them to build proteins or nitrogen contaning compounds.

Average growth population growth